Hi. Yes, it is a copy made in Eibar (Spain), of a Deringer percussion pistol. Branded "Mendi". Cheap and decorative gun, manufactured in the early seventies. Previous to what was later Jukar and Dikar (CVA for the USA market). It sure is smoothbore. It can be polished and personalized, but only for decoration. Greetings from Spain.
I use to buy those in kit form from DGW then assemble them and sell them. They were a novelty and would go bang - most of the time. They were made in Spain and if I remember correctly their cost as a kit was around $20.00. The shield and escutcheon were chrome plated on the kits that I purchased if I remember correctly.