The W is the black variant.
W means with windows keys.
AT101 and AT102 do not have Windows keys, and all but the very very earliest ones have black Alps, but there are those with salmon Alps which are rare. Some of the very early ones have PBT key caps, but I don't think that there is a consistent relationship between those and the ones with the salmon switches. You can't really go by "old logo" either, although those were more likely to have the early components.
"1" means ANSI and "2" means ISO.
AT101W and AT102W do have Windows keys, have black Alps, and are also available with black cases, which while not rare, they are uncommon.
Last, there were AT101R and AT102R which had rubber domes.