The mystery is solved. Well, kinda, anyway.
I sent my choke tube to Shane at Carlson's, after trying two he sent me. It turns out that mine is a custom, probably home built. The threads are not standard and there is no other commercial choke to match it. The threads start out as about 36tpi and wander off to something a bit finer. The threads in the barrel match.
Shane's contact at CVA, who has worked there for years states that all their chokes were purchased as Winchester/Mossberg/Invector standards, and those will fit any CVA factory threaded barrel. Those are 32tpi.
So, this answers the question of what chokes fit the CVA shotguns, as well as we are going to get.