we never trust factory primmers in my shop.we do just what you did.we have a real issue with these primers.they work good but the finished paint is very susseptable to chipping.i cant say ive used new harly parts so this might not be a fair jugment but we've had the problem on gm ford dodge japenese and al after market panels.in my opinion a good epoxy wont let you down and for the sake of a little extra work why take the chance.i've seen the hours you put into your work hoss .bet you dont want to do it twice.lol.cyas
It's also a good idea to have them pressure tested, even if they are new. The worst time to find out they leak at a gusset is when they are painted and you put gas in the tank. Been there done that. AL