It has a WD93028-X (20MB XT IDE) drive in it.
No RAM.
Rev 6.1 ROMs. (I do not have any rev 7 roms here or I would put them in it.)
It has both the internal the power connectors
So, nothing exciting to write home about... but it's a working 590 in very nice condition. (no dints, scratches, dirt, etc) I'll take a picture of it and you tell me if it's "yellowed" -- I can't really tell because Amiga 500's were all beige to begin with and not white.