I do recall seeing the anchor, faint as you say.
I imaged the drum, and I have attached the panels. Maybe you can tell me more about it.
It is importnat that I do not get my hopes up about acquiring this Thomspon (and you all shouldn't, either!). I can think of many, many reasons why it will not happen. I cannot believe I'd have been the first to ask, or make an offer. It is a big department, so they may not need the cash. It may not be transferable. Perhaps it was confiscated and never registered. Which leads me to my next question.
What can we suppose about the gun from the fact it has GI parts in it? Could it have been bought by the agency post-WWII? It would seem to me that the gun would not have seen any "gangster action" (which is the going story there at the SO). If it had been confiscated in the roaring thirties from some gangster, it would not likely have GI parts in it, at least it doesn't seem like it. I am sure others can posit some theories as well....
PS: Poprivit: How is it that the NFA gave you info on the serial number of that SO gun? Did you work there?