In Rainey's pictures you can see that the locks are basically all the same and probably copied after Holland and Holland. You can also see that there are 5 screw posts (blued) and 3 polished screw posts acting as axels, that is counting the one on the long leg of the lock that holds the mainspring in place. Someone years ago came up with the bright idea of using the tumbler axel as a cocking indicator by putting a slot in it.

Before the turn of the last century, many of the lock plates were machined out to hold the mainspring in.

Some of the best locks are engine turned supposedly to hold a light film of oil.

David