I'm pretty excited. I "found" a previously unknown to me version of the old C.P. wrench knife. It's the one on the left below. It has a flat base on the lower jaw insert, and the insert isn't pinned through the handle like others I've seen. It also doesn't have a screwdriver blade on the end of the handle. I'm guessing it was a really early version.
Middle one in the photo I've had for years. It has a flat backspring riveted to the handle. (Just like the "early" model on the left.) But it has a curved base to the lower jaw insert, and a screwdriver.
Right hand one is the later production version I'm guessing. It has a bent steel backspring, and uses a bolt for the upper jaw to pivot on. It also has a different stamping than the earlier two.