It might be extra memory. I used to have an A1000 and the RAM expansion was in a hatch at the front of the A1000 case if I remember rightly.
On the picture you can't see all the chips clearly, but the chips that I can see the numbers on are just garden variety 74LS series chips, so I'm not so sure it's a RAM board.
If it is a RAM expansion, then it's likely only the 8 chips in the bottom right hand corner of the board are RAM chips and probably only 256K at a guess.
I'd say that board could have other functions beside RAM.
But hey, I could be wrong. wouldn't be the first time :-))
