I sure missed the part about the long action, but I don't know how a long-action gun could incorporate the short-action sculpted/fishhook hammer without some kind of tuning or smithing. Maybe I am just under-informed about the possibility of that kind of modification.
I'm now considering that this could be some kind of put-together gun with BSR parts hung on an old M&P frame. Did you happen to notice if it had the four-line or one-line address block, or even no address block at all?
Did you read the serial number from the butt of the gun or was it written by the dealer on a hang tag?
I feel myself going all OCD about this gun. Maybe I need to take a walk and swear off coffee for the day.