OK, I have some of the offending ammunition at hand, now.
It’s in a black box, with a picture of a wolf on it. Labeled “Wolf Performance Ammunition”, 15gr FMJ.
The cases are metallic grey in appearance, smooth but do not feel “slick” the way brass or nickel-plated cases do (to me). If there’s any lacquer, it’s very thin. Seems to be some sort of coating, though.
I purchased it within the last two years.
Yep, sounds like the newer polymer coated ammo.
Just to add, I’ve shot better than 10,000 rounds of the Wolf 230gr. Poly ammo through my 45’s and maybe half that of the 115gr. through my 9mm’s without issue.