At first reaction i realized these could be Portuguese; the tradional so called "egg butt" pistols. This eventuality brought me a significant enthusiasm
. But after consulting someone experienced in this area, who dealt with several egg butt pistols from both XVIII-XIX century, with the three different types of lock, i was told these could be indeed Spanish versions.
If you have James Lavin "A history of SPANISH FIREMARS", you may be interested in observing gunmaker's mark #96 (page 277) named Seria. Maybe this is your guy.