That grill guard may not be the same width as your frame rails, you would need to fabricate the brackets for it out of 1\4" steel plate to mate to the outside edges. If you use the bolt holes for tow hooks, you would also need to bend the brackets at the mount point and drill the holes. There are plenty of GG brackets you can use as a template. You might even be able to just buy some replacement Aries etc and use them.
You also need some upper support. This can be as chincy as you're willing to risk, but having this shoved in to the radiator isnt going to be a good day. So the upper brackets should be quite strong braced against something quite strong. You could probably modify a flat pry bar or any other strong flat bar.
Then there's the refinishing. If it were me, I would take it somewhere to be blasted, primed and power coated or the equivalent with Duplicolor or Rustoleum.
Money wise it would still make sense and you would have a strong custom piece with a brand new paint job.
.