Long Johns Wolf might answer that question better perhaps... But Mike, I don't thing the Eastern Block outfit ever amounted to anything than a few mockups and some perhaps, seed money pre-orders forfeited
If I had the receiver in question, 1st. I check if the screws were metric.... if not I'd lean toward the Navy Arms Henry that was modified to King's improvement , perhaps with Uberti or ? 66 loading gate... this seems the most plausible, at least
out of the 1000 made, the most likely candidate.
There is also the brilliant gunsmith chap that makes his own Volcanic & Henry's that post here from time to time , perhaps one of his fine creations escaped
it also might be , and early prototype , that Val had produced in Gardone .
whatever the case Mr Fanning is a very fortunate fellow, if I had it, I'd be all over the receiver and have my FAVORITE retired Gunsmith fit a 44 barrel ....yep that's what I'd do