The 2091 needs 256x4 chips(usually marked 514256, 44c256 etc or similar but there are many other #'s) .. 8 chips make 1MB.
the 2091 can take 512K,1M,2MB.. be sure to set the jumper on the card to signify what is installed.for 1 Mb you would fill sockets u14-u21 (look inside the socket for #'s)
I thought the placement was a problem, BUT none of the docs I can find say a word about chip placement. I set the jumper right, but I received the card with the RAM installed this way - so I wasn't sure.
I am lucky enough that this card has the revision 08 SCSI chip in it - thanks to another Aorg member.
btw the chips are marked "p21014 - 10" - I'll look them up later.