Whats up with that ? That's NOT many miles at all for a repair like that ALREADY. Did the dealer give a reason?
I doubt the dealer could give a real reason, since it sounds (as hd-dude mentioned) like a shotgun diagnostic approach was used. Once they tear something down they are bound to replace something or they won't be reimbursed under warranty. Harley doesn't pay for fishing expeditions by their dealers.
Most dealers wouldn't have gone into the cam chest at all unless the engine was exhibiting symptoms while in their possession. They don't usually take a customer's word for these sorts of intermittent problems, expecially if they can't duplicate the problem themselves. It's quite possible there was nothing wrong with the lifters either, but as I said the only chance they have of being reimbursed for looking around is to replace something (and hope Harley doesn't ask for the parts back and test them).
There are a lot of things that could cause a ticking noise that starts suddenly and then goes away just as suddenly. One could be a piece of trash in the lifter preventing the internal valve from seating I suppose.
Jerry