Durrs-Egg is a style of lock. Off-hand I don't know if it is the manufacturers' name or just the style. The engraving on this gun, not being the best of quality, looks like it would be a 17th century Saturday Night Special. You can see the file marks on the hammer, too. I think that this was made for the less sophisticated that would not know that D EGG was not a Durrs-Egg.
The Doc is out now.