Looks like the keypads from Jens Mueller's JKCEMU

This SC1 program, I don't think it's by VEB Polytechnik. And there is no "Schachcomputer SC-880". It must be by a fanatic Poly-Computer 880 user, I assume Dr.Scheuschner, since it's similar to SLC1.

He has a website btw: https://dr-scheuschner.de/start/schachcomputer-slc1/