Well, based on what your future intentions seem to be I wouldn't go clean. I'd make sure to be only wearing gens from here on forward and in your future conversations hint at the fact that you've seen some top shelf quality reps and that you too own one or two along with your gens. Then offer to bring one to a future meeting. IMHO, that would still leave your reputation intact and introduce reps into the mix. All this could spur more indepth discussions with him about watches in general and bring you two closer. I think in this fashion you can own up to the fact that you own reps without having to outright admit that you lied to him.
Yes, it's cop out, but it's an option. But... I also think honesty is always the way.