I've got a Spanish flintlock 28 gauge I picked up on gunbroker for a little over $100 back in 2014. It looks like the percussion gun in the video linked above only hasn't had the barrel chopped off. I'm guessing around a 28 inch barrel. Half stock like the one in the video. When I bought it the seller neglected to mention it would not stay at full cock. But I bought a flintlock shotgun in otherwise excellent condition for a hundred bucks so I didn't complain. Stuck it back in the safe and, just recently, got it out and pulled the lock. Gonna try to get it running but may have to look on the forum for advice as I have never worked on a flintlock action before. Anywho,,, I don't remember the brand and all I recall seeing stamped on the barrel were some proof marks. I believe it to be made by a company that made Mendi pistols. They show up on gunbroker from time to time. I think there is one on there now in .41. I also had a full stocked rifle in .36 for a while that was made by the same people. Ugliest thing you ever saw but it was a great shooter. They do exist but are getting harder to come by. If his price is right it might be nice to have.