From what I can make out from the crude Google translation from Japanese to English, the evolution is something like this.
AL-10A1 - the original substrate, initially used for 'Moon Alien', then later for their new game 'Moon Cresta'
An AL-10A1 'upgrade kit', as seen in the lower middle photo, was available for purchase to upgrade 'Moon Alien' cabs in the field to 'Moon Cresta'.
Note the potted CPU and Character generator modules, an attempt to guard against pirating as a result of this cheaper upgrade kit.
MC-1 - dedicated Moon Cresta hardware. Apart from the 'MC-1' branding, there appears to be no other difference from the AL-10A1 hardware
MC-1FJ - intended as a complete field upgrade kt, comprising of the whole PCB. Appears to have no difference in hardware, compared to the predecessor PCB's
SMC-2FJ - Super Moon Cresta, a game which apparently did exist but which I have personally not encountered here in Australia. This hardware may also have been used for 'Moon Quasar', the sequel to Moon Cresta. My own personal reverse engineering of this hardware reveals that the address decoding for the character generator ROMS differs to previous iterations of the board. Forever hopeful that someone out there can provide a scan of a Moon Quasar manual or schematic, so I can confirm my findings.
AL-1B, the edge connector version of the series, intended to provide an easy Moon Alien or Moon Cresta upgrade path for Galaxian cabs. The pinout of the edge connector is the same as Galaxian.