You've done a nice job of repairing the board

I've seen game chips soldered directly to the board before ,but it wasn't factory ,just bodgy.
I wouldn't think that Stern would have done it from factory either ,but you just never know.

Several early Stern machines used the same game chips ,must have saved them money on programming costs.
Wild Fyre and Dracula...interchangeable
Cosmic princess and Magic....interchangeable
Stingray and pinball.....interchangeable

That's all i can think of off the top of my head