Yep. The boards were used in the 11/70, the 11/730, and the 11/750.
I don't know if
you could use the 256K boards (populated with 4116s) in the 11/730 due
to the tri-voltage
4116s, but even if they worked, you wouldn't want to - 5 of them just
isn't that much RAM.
I am pretty sure (havng read and re-read the printset, I am restroring
an 11/730 at the moment) that you can't use 256K boards in that machine.
The memory address decoder (which IIRC is on the MCT board, part of
the CPU) assumes 1M boards.
Anyway, as you say, you would not want that little memory.
-tony