I found another holster for my Rossi M720 on e-bay, being a lefty and having a 3" barrel gun makes finding a good fitting holster hard to come by. This holster was made by Bucheimer for the S&W 13 w/3" barrel ( model 01-604 16 LH )
I have a "Bucheimer Concealer" holster for a 1911. Looks very similar to the one you have in its construction details - particularly the double-reinforced thumb-break. My only issue with it that it won't snap under the hammer so as to permit condition 1 carry.
But yours is the only other Bucheimer I've ever seen.