In comparing my OEM lifters to the Comp Cam replacements, the biggest difference to the eye...is how the roller bearing shaft is secured within the lifter. The factory lifter uses an internal snap ring on the shaft ends and the Comp Cams one uses a cheaper method of just mushrooming the ends into the lifter shell. Many pictures/photos of the various lifters do not show these important characteristics. I had a set of GEN-IV lifters too and those used the better engineered snap ring retainers as well. When you get these MOPAR/Elgin lifters, let us know how the roller shaft pins are secured. I think that will be the big indicator as to the question of OEM or not.
"Aspice, officio fungeris sine spe honoris amplioris." (Face it, you're stuck in a dead end job.)