Help identifying mystery Dataram VAX-11/750 (?) board

Hi all -- Picked up a board advertised as a "4mb memory board" for a VAX-11/750. It's made by Dataram and I'm unsure of the model number, based on photos of it. I just noticed that rather than being a hex-height board that goes in the memory backplane, it looks like a board that goes in the main CMI backplane. It also appears to have 16mb of ECC memory on it, rather than 4mb. My thought is either (1) it's not actually for an 11/750 (in which case I'm curious what it would go into), or (2) it completely replaces the memory controller and standard memory and gives you 16mb in the 750. (Or it could be that it's something else entirely.) If anyone has any ideas or has a source of information, let me know. I put up a few pictures here: http://yahozna.dyndns.org/scratch/dataram/ Thanks as always, - Josh