Joe, I have a flintlock era John Manton, later converted to percussion, with the grip safety. I have no way of knowing whether it was installed on the gun when it was made (1809) or when it was later converted to percussion by John Manton & Son. For the reasons mentioned in my earlier post the grip safety would have worked well in a duck blind. I think that my John Manton (8.4 lbs. with strap swivels) likely was used as a duck gun.
Richard, thinking about it, the grip safety was a pretty good idea. In the time these flinters were made there was only walk up hunting and on a wild flush there isn’t much time to cock the hammers before the birds or hares are out of range, especially with the “ammunition” available. Carrying the gun at full cock and then merely raising it to the shoulder would put a lot of extra game in the bag. So despite the obvious dangers of a grip safety I can understand why they used them. Been there, done it. Today when I have a dog on point I go in for the flush with both hammers full cocked and there isn’t any safety other than me. I do tell my hunting partner “Fire in the hole” when I pull them back.