There isnt a marking or any indication of a manufacturer, And the date codes on that accelerator board corroborate the date code of the fan mounted in the machine, etc.. So there is no reason to believe this wasnt installed by General Computer. 

The machine does have an issue with or without the accelerator installed. the blinking ? icon isnt blinking. it says solid. Itll boot from floppy, but not from SCSI. my other mac plus board does the same thing. strange. 

But I digress, I derailed this thread enough. lol.