I would say that it would have been extremely unlikely that anyone other than the factory would have made that barrel. There were only 3 documented in the SWCA database and all in 44 Russian. Also, they were all in the mid-35,000 range. It would be impossible to come up with the number made without factory documentation, so not sure how the auction house found the information. SCSW4 has no information validating the number made. I have seen letters that state numbers like that and could be construed as the total production, but it could be that 50 were sent out at once in the mid-35,000 range, since I believe there were more than 50 made?