I don't think it's RIR. Correct me if I'm wrong, but from these photos it looks like his butt fluff is black. If so, that would mean he's not a RIR.
Also, I can't tell body shape from these photos, and that's really important in RIR.
Finally, I'm not sure if RIR should have that black bar across the flight feathers in the wing.
He does have a nice mahogany (vs red) color, though.
You might want to post this in the breeds section and ask again, since I only have a superficial knowledge of the breed; but I'd warn you that so many people are sold "RIR" from hatcheries that are really Production Red (and are red colored, with an upright body shape and green rather than black tail) that many people will give you wrong information. You want to find someone breeding Heritage Rhode Island Reds to be sure.