As for the rockwell chip I have no clue. if it's an MM7x it's probably dumpable; this would be tellable via the pinout.
I'll put together the info I've collected on the Rockwell chips. I've found 3 different families so far in the Mattel games: B60xx in Auto Race and Battlestar Galactica, B61xx in Football and Baseball, and B90xx in Brain Baffler and now Horoscope. I've looked closely at the B60xx and B61xx pinouts and die shots, and they are not MM7x, but I think they are related.