Here's my photos of a NIB IBM Industrial Model M from December 1988 - this one has the rarer Black Square Logo on the upper right hand side.
I no longer have this one but it was one of the rarer keyboards I've owned. I don't know of too many pre-1988 NIB Industrial Model Ms. This one has the wire stabilizers on the vertical + and Enter keys and the wires connecting the LED board. I also opened up the keyboard.