Wayne, from your serial number I would say this gun was made in 1887. There were probably as many 10 gauges as there were 12 gauges made. What makes yours unique is that it looks to be built on an Extra Heavy Weight frame. Back then there was no extra charge for a 10 or 12 gauge in either a Heavy Weight, Extra Heavy Weight or Medium Weight gun. There are no records and it would be just speculation as to how many were made as serial numbers most likely were not consecutively numbered. The Trap Grade butt plate was an advertising ploy as trap shooting was just getting started and in their ads mentioned that these guns were good at the traps as well as the field, but in the case of your gun I don't think it was used much at the traps as it was in the duck blind.