Dang, it's a four layer jobby! Well, with an installed ROM and the shift registers in place, it would still be possible to recreate all the switching and, hence, the schematic.
The connector apparently is a Pancon 130-332-523 (obviously), which is no longer available (sadly). It is, however, designed after DIN 41612 and there are manufacturers producing similar substitutes (thankfully). One might need to rip out the inner connector row, however, as I did not find yet a 32-pole connector with 3 rows, where the inner row is not used. I found this though:
https://www.mouser.de/ProductDetail/HARTING/09282486804791?qs=sGAEpiMZZMud62t8luTOJjrQXusuevCyur2NPCEHnCLKUNNf9%2FwINw%3D%3DAlso from a respectable german manufacturer (thank you, Keithley, for thinking of us Krauts), should fit mechanically, it might just have a lower insulation spec then when assembled on the PCB due to the lack of clearance.
So, with this part one might be able to recreate something with worse specs.
The project will clock in at around 100$ though as especially the relais are quite expensive.
https://www.mouser.de/ProductDetail/KEMET/EE2-3SNUH-L?qs=BenOyfdfArr1F1eFnWGDbw%3D%3DThe case would be printed in most cases (ha!) I assume.
I'm just wondering: The functionality of the shift registers could be implemented by a microcontroller. This way it can be reconfigured without spinning a new board.