[northernlights]

The factory spec. has a wide tolerance, the Truxxx spec. is more specific.

You are correct.......

 

[northernlights]

The guy I bought the truck from ran different sized tires on the front and rear axle(245/70 on front and 265/70 on rear

Bummer, not good.

 

[northernlights]

You have a bit over an inch from front to rear tire diameter,depends on how long that went on, maybe they just put tires on it to sell it. Drive it and dont worry about it for now, you've invested some dollars in it on some good maintenance points so just keep an eye on things. Good vehicle for her just listen to her if anything comes up. Congrates on your new used RL.
Edit: Dont worry about the CV, that wouldnt have anythin to do with the different tire size.