and the die label is CMS54C / KMS560. There's also another 560 on the die.
I'm pretty sure the "brochure" mentioned in patent 4,504,062 is part of the patent wrapper ($55), but it doesn't look like it has any more info than the 1990 data book. I did some other patent searches, but didn't find much else. A Google Patents search for "Sharp SM" found SM4, SM530 and SM551, and "Sharp microcomputer" found a suntan indicator watch with an SM530.
Does anyone know what game is in patent US4895376A?