This is my personal "pet peeve" with lifters for Chrysler engines.

1) 5/16 dia is the "normal" pushrod ball dia.
2) Many companies make the lifters to fit both 3/8 and 5/16.

But trying to find out which are and which are not is like pulling teeth (from your own mouth). FWIW, I am guessing the 5/16" dia pushrod ball end is just fine. I have run both 3/8 and 5/16 ends with Comp cams lifters. And 3/8 pushrod ends with MP solid lifters; but others have run 5/16" pushrod ends.