I would take it to my dealer also, 2002 HD shouldnt have oil leaking at all, had a 2002 Dyna and never leaked any oil, burned some oil as the miles added up.
If you only have 28000 then there is a problem. Either leaking or burning! At 1/2 quart a month you probably would see oil spots under the bike where it sat overnight, but with that little amount you probably wouldn't see any smoking. Shop should be able to diagnose pretty quickly.