Guilty as charged

Thanks for your good wishes! It's not going to be easy to find somebody who has one of those they want to sell. I really should take off the sideplate and make sure the lockwork has the early ball end mainspring strut if I do find an early hammer. If I don't check I might have to start hunting an early strut, too. I imagine they are just as hard to find as an early hammer.
The ball end strut and compatible hammer base inlet goes from the beginning of production and was retained even after 1954-55 when the later type hammer started to be used and continued until late 1961 - early 1962. That's when S&W changed to a Y shaped strut which engages a horizontal pin inside the base of the hammer. The base of the hammers which take the ball end strut don't have a cross pin in the hammer base inlet.

So when you look at the profile of a late Baby Chief with a late hammer you can't tell without popping the sideplate which style strut it has. The strut that sits atop the coil mainspring will take both the early and late struts and it's an easy installment, even for a dummy like me.

The odds are that the hammer on my Baby Chiefs (SN 38953) is a replacement rather than a very early example with the late hammer. I'd sooner have the early style hammer, but you can't have everything. It's a shooter and carry gun anyway.