No I would not buy a rep of a gen I already own. What is the point? Unless you own a real red sub or some other rare piece that is appreciating in value you may as well wear the gen. After all, since finding this forum I no longer have to pay AD repair prices to repair the gens and I know they are fixed properly.
I also have not bought a gen based on a rep. But if I add up what I have spent on reps I could be wearing any number of gens. Then again I wouldn't have that wonderful choice of WM's, MBW's, DW's, Original Movement PAM's, Breitlings, VC's, etc.