Hi Dave,
Those locks were made from castings of an original pair of Wogdon dueling pistols from about 1780. I bought the castings from Blackley's in England. All of the screws and springs were made by me. The wide safety slide is the style used on those particular locks. Most safety slides were narrower and did not hide the sear screw. Dave, these are small locks just 4.25" long so every component has to fit in a small space. A fowler lock would be easier to build because you have more room to fit parts and margins for error are bigger. Below are pictures of the finished pistols. The low angle daylight (Alaska in winter) unfortunately causes a lot of glare in the photos.
Gary, you are completely correct. Sometimes it seems every dealer calls a pair of cased pistols "dueling pistols". Traveling pistols, horse pistols, overcoat pistols, fowlers, blunderbusses, and even some quasi-military guns had sliding safeties. Interestingly, one of the best pair of dueling pistols made by Wogdon for the British royal family did not have safety slides. I find the slide to be a pain to operate. To release it for shooting, you have to pull the cock back slightly to release pressure on the bolt and slide the safety. That takes two hands. I think if you needed to carry the pistol primed and loaded, which means it had to be at half cock, the safety would be useful but it sure doesn't make it easy to point and shoot.
dave