Thank you. This is more interesting. Do you know when this design was introduced?I think the Colt Screw-less SAA really is rather exotic.
It's been years since I saw one, but as I recall the hammer and trigger assembly are installed from the BOTTOM of the frame.
There are slots in the inside of the frame for the hammer and trigger pivot pins.
Instead of screws passing through the frame, there are short pivot pins inserted in the hammer and trigger.
The parts with the pivot pins are slide up inside the frame, and held in place by the trigger guard.
There are no pins or screws visible from the outside.