[puzzle]

Well, there's one guy (Ron Nicholson, who later worked on the N64 chipset) whose signature appears in both machines. Perhaps he thought to apply Job's idea to the Amiga 1000.

As for other machines, I don't know of other signatures, but there are often Easter eggs. Commodore machines had funny stuff on their PCBs: codenames Rock Lobster, Junebug, plus the Fred/Wilma LEDs, etc. Lots of integrated circuits from several companies had artwork in unused areas of the silicon die.