Hi Razor,
I've built dueling pistols following traditional British lines and features. They are not easy to do right. Blackley's has the only good selection of lock castings that you are looking for. You have to build the lock. All of the commercially made and assembled pistol locks lack the safety bolt and are too large. The Mortimer lock from Pedersoli is an exception but having worked on several, I am not impressed and they don't live up to British quality. In addition, no one commercially manufactures appropriate trigger guards. The bows on dueling pistols were larger than the pistol trigger guards sold today for 18th and early 19th century guns. The essence of British dueling pistols was perfect function, superb workmanship, and great feel in the hand. You really have to handle a few to get it right.
dave