I agree with Mike Franzen. The mentioned gun, 181,261, is about the high serial number of scroll engraved single traps. Who has a higher number single trap without a pigeon in the engraving pattern?

SBT 181261
 

There are two old threads on this with better pictures on 9/23/16 and the letter on 10/16 if interested. I don’t know how to bring them forward.