I think I'll give the product manager at Dixie a try. I've written to both Pedersoli and ArmiSport in Italy and included photos, but neither has replied. The original literature does state that the gun maker is a very small operation, but has been in continuous operation since the early 1800s, which should help narrow it down considerably. I wish the copywriters of the Beeman catalog had just named the maker, but perhaps they were under some sort of contractual obligation not to (although I can't imagine why). The gun is similar to the La Page models, although the La Page guns I've seen vary considerably in architecture. The closest thing I could find to it is the Pedersoli "Mang"
Standard model.
Thanks for the tips and commenets.