I think it probably did have a name on there, but it probably would not have been the maker. Many English guns were engraved with the name of the retailer, not the maker. Anyway, the gun is of good quality; the "fish scale" hammers and the gold inlay show that very well.
I hope I don't have to tell you not to shoot it, even with black powder. Those old twist or laminated barrels can let go any time, not only destroying the gun but possibly injuring the shooter. It is a beautiful family heirloom and deserves a prominent place of retirement on the wall or above a fireplace.
Jim