Ehhh, mess with it anyway! Tell her you need certain things to allow her(you) to get better mileage, more power, less hesitation, etc, lol!
I optioned mine to have the 3.73 and the heavy duty trailer tow when I bought it new. The 7 pin is a good sign that it's got the heavy tow, however, they were also known to come through with the 3.55 as well. Is it 4x4? Then I'd venture a guess that it's 3.73, if 4x2 might have other set.
Tires, so many to choose from. You'll get varying opinions, but I will say I've noticed down here, the concrete roads seem to chew up everything I've had on mine. The ContiTrac wore out at 30k, and my Nittos are on the way out at almost 60k. It's all good, new tires are in the budget this spring and I'm moving up in size after the lift anyway. 4wheelparts in Plano has helped me out in the past and I'll be a return customer.
Anything else, just fire away, always fun to help a neighbor out!