One way you could investigate further while you have the valve covers off is to pull the plugs (follow the TSB on removal, limit torque to 33 ft-lb, on initial breaking them loose for no more than 1/4 turn, then good 1 sec. spray of SeaFoam Deep Creep, wait at least 30 min -- you can work though initial 1/4 turn of other plugs, then finish) Hopefully that was fixed by 2010, but old TSB was TSB 08-7-6.
Anyway, with the plugs out you could use a bore-scope and look at the top of each piston for any contact with the valves (and where the pistons are relative to the valves to know if you had anything to worry about to begin with). I really doubt you would have damaged anything snugging the cam caps down even 180 degrees out as long as you were not turning the crank. Yes, there is a potential for bending a valve, but I would think there would be ample indication that "hey, something's hitting" as you were snugging the cap bolts down. Once you get the cam timed and roller-followers on, you can manually turn the crack (clockwise) though 2 rotations and make sure all valves are opening/closing and not binding. If I were in you position and I had any lingering doubt, I'd pull the plugs and borrow a bore-scope from an auto-parts store to at least have a look. It's a good time to change plugs anyway (don't forget the anti-seize for putting the new ones in). I just put the 3rd set in when I did the oil pump, chains, phasers and VCT solenoids at 254K.
After using the 3-part spring compressor, it takes a bit of practice, but once your have found the 400 ways the roller-followers won't come out or go back on, you hit your rhythm, and should be able to do each in 30 sec or so. I had to use a dremel and remove a few thousandths of material on the inside and outside of each of the long legs where they fit around the cam lobes to clean up poor machining when the tool was made, and shave a bit off the "heel" of the foot that goes over the valve spring (to allow it to maneuver on/off the valves closest to the head casting, especially No. 4 and 8 most rear valve). The fork, as the makuloco video shows, must fit fully back against the cam - no almost. Otherwise you get flex in the fork and the valve will not compress enough to allow you to remove/install the roller-follower. I had to shave a few thousandths off the inner and outer of the fork in the cam-lobe area to prevent it from rubbing against the head casting in the area of the cam journals (bearing surfaces).
For installing the roller-follower, I found positioning the roller-follower where it was inline with the final position, but with tip that pushes the valve being about 1/4" beyond its final position and the cup that fits on the adjuster was an equal amount in front of the adjuster so your final movement to install it was just snapping it back the 1/4" so the roller is under the cam and the adjuster snaps into the cup. (it's all one motion, you've already lined it up, you just pull it back towards the cam so it snaps in place) Intakes go down from the top, exhausts come up from the bottom. After screwing around and doing it the 400 ways that didn't work, once I hit on this approach, they all went in like butter. I used a pick, like a small phillips screwdriver with the last 1/2" bent 90 degrees to help position the roller-followers before snapping them back in place -- that's where the real work is. (this is the part I wish makuloco would have gone over a bit more, though you could tell from the video he didn't have a set system down yet)
Absent a bore-scope, since you have the cam out, you could remove the roller-followers, put the cam in place and then do a quick compression of each of the springs, pressing on the valve-stem to move the valve in with the springs to make sure the keepers stay in place. As long as none of the valves are bound in place, that's at least an assurance there wasn't any significant bending that took place. You can fully depress the value springs to the limit of the 3-part tool without worrying about contact with the top of the piston. There is at least that much clearance between the piston and values. (It's not like a race-motor where you have to place a thin layer of clay on the piston tops and pre-assemble the heads on the block, set the valve lash and rotate the crank to ensure valve clearance)
Other than putting a scope down to look at the piston tops and running the values up/down using the compressor, I can't think of anything else to try. I'm sure somewhere the crank specs exists that would tell you what the position of the pistons were for pistons 1-4 with the crank timed at the 6:00 position. If none of the pistons were at or near TDC, then you wouldn't have anything to worry about anyway. You have the cam, so you can look at what the lobe positions are when 180 degrees out (the "L" is at the 10:00-11:00 position) and see if any of the valves had a chance of being fully opened.
I'd put the cam in without the roller-followers, or at the very most, only those roller-followers where the cam isn't providing any lift when the "R" is in the proper position between the timing links on the chain for bank-1. (and even that's pushing it). With as easy as the roller-followers are to put in (once you figure it out), it makes sense to just do them after the cam is torqued in place.
Let us know which way you go and what you find. Those are the thoughts I had come to mind and what I would do in the same position. And good luck regardless of which way you go.
