@tubetime
I was going to say that it *looks* like a CDC part. They had a bunch of modules at the Living Computer Museum. They also had modern replacements. I don't recall the details but it was something like "this brick is 2k of memory" and the replacement was an expanse of naked PCB with, like, two chips on it.

The LCM is sort of closed, but I think the CDC is still running and being cared for. Should I look for a contact for you?

livingcomputers.org/Computer-C