I won this Ms. Pac-Man prototype in an auction, and it turned out to be very different form the final version. Here is a picture of the PCB and the ROM. Enjoy
After taking byte-shifting into account...there's really only about 160 bytes that differ (and most of those appear to be garbage values that are never used). Notable differences are the bit masks (for flicker?) right at the top, and some extra code (bugfixes?) in the final that's not part of the WIP...at $F143 & $F58F.