Here are the Plus One and Funtronics Jacks die shots:

The Plus One die stuck to the plastic, but it looks like there was also a black overlay of some sort. I've seen something similar with a few 3851 and 3870 dies.

It looks like Jacks has all the signals bonded out that are needed to dump the ROM. Pin one is the octagonal pad at center bottom, and all pins but 17 are bonded. I'm a little confused since that's G0 and it seems like if they used the other G outputs that they'd use G0 first.

Under higher magnification, I can see the ROM bits! So I'll dump Jacks electronically and transcribe the bits visually and figure out the physical to logical bit ordering. Then I'll see if I can clean up the Plus One die enough to read all the bits visually.