the only time a harley doesn't leak....
is when it's empty
anyway, i wouldn't be concerned about a leak, especially if it's been fixed. UNLESS is was a severe leak and it was run with a really low oil level. that can and will score bearings, etc.
as far as being raced?? so what, most of the dipshit squids around here beat thier bikes harder than a racer (meaning they don''t have a clue what the hell they're doing, so it's a different, worse, kind of abuse). most racers are pretty good about maintenance, cuz they gotta keep it running great to compete. at least on a racetrack it's being used for what it was pretty much designed for. modern jap sportbikes are built so well that they'll stand up to a HELL of alot of abuse before they actually pop. i've seen bikes with 300+hp on bone stock bottom ends, and they hold up fine.