You'd have to partially de-glob Top Gun and TMNT to get to the test pin. And I'm not sure where the ROM contents are output, but not all the strobe outputs are bonded out. I need to look at the R-Zone carts again to see if they are the same way, or if they are more amenable to testing/dumping.

The Top Gun patent doesn't seem to have the correct button wiring. I'm sure you could figure it out easily in emulation, but here's what I see:

    S1     S2     S3
K1  Sel   Left    On
K2  Snd    Up     --
K3  Off   Down    --
K4  Fire  Right   --

I vectorized some of the PCB:

Pin 1 is lower right.