OBD1 PCM interchange/compatibility, 5.2 vs 5.9

I think it was just worn out, didn't look like a lot of maintenance, and almost 250k on the truck. PO parked it when the trans went south, so evidently it was still running. I've been told by a couple mechanics I trust that the PCMs are rarely bad, but folks change them out while chasing engine problems. I've had a slew of issues with my trucks over the years, never been the computer.