I am not sure..I photoshopped it and enlarged/contrast enh, etc., and came up with an 8237 ir 8257 for the left-hand 40pin chip (either way its a DMA controller), and then the Toshiba is static ram, and I can't make out much more on the big chips...
The traces look pretty clean and professional - no undercut apparent, straight and consistent. It might have been done in a small PCB house, and it had to be from someone who had layout tools (since stuff like OrCad and such was pretty rare in 'the '70s). Had to have been done on a mini/workstation, I think...
Can the OP get a closer/clearer set of pics for the chips--that *might* tell us more.
gwk