PDP11 NSC RAM questions

I've purchased a memory board for PDP11. It appears to be a National Semiconductor Q-BUS memory card. It has 980110014-001 on it. I find (currently) no markings saying like NS23D, NS23M, NS23S, NS23E, etc.... It is populated with MMC3764N-15 chips. There are 144 chips total. I'm still a newbie on 11s... but, if my internet searches are correct those chips are 64k x 1 ram modules. So it takes 8 of them to make 64 kilobytes. Assuming there is parity, 144/9 make 16 sets of 9 chips each with 64 kilobytes + 1 parity bit per byte (9th chip). This math makes it out to me a 1MB module. Can anyone confirm that is what it is ? I bought it as a 4MB module. Also, I believe this came out of an 11/73. Will this work in an 11/83, and if so, does it operate as PMI memory ? Thanks in advance from all you PDP11 gurus out there. And... if this isn't PMI memory, and if is only a 1MB board, would anyone want to take in in trade towards a M8637-EF (MSV11-JE) to go along with the existing MSV11-JE I have. -- Curt