Chess Records - Deep Groove

Might not be the place to ask, but I can't seem to find answer anywhere else, and I believe Mr. LJC collected blues records in the past. Does anyone have any info on deep groove pressings and Chess Records. Specifically at the Sheldon pressing plant. I recently bought Howlin’ Wolf’s Moanin’ in the Moonlight from a local store and it has all of the hallmarks of an original except it doesn’t have deep groove.

Thanks all.