Hydraulic FT issues/rumors?

Supposedly an Erson cam and lifters installed by previous owner, no idea on how many miles on them prior or what year manufactured, but after 3 years and maybe 10,000 miles on sons 360 (78 Magnum) it developed the dreaded clack. Assumed a collapsed lifter or bad rocker arm. During manifold swap, lifter and rocker arm inspection we found one concave lifter face and rounded cam lobe. All others literally look like new.