Craig, I'm out of my depth, but member Dave Noreen's DGJ autumn 2004 article Evolution of the Sterlingworth, Part 1, says"

"When the 12 gauge Sterlingworth debuted in 1910, the guns were marked as being the product of 'The Sterlingworth Company' both on the sides of the frame and on the top of the left barrel." No mention of pin gun.

I'll see if there's more in Part 2, if I have it.