Well ....
A1000 KBDs come with a "telephone-plug" a special layout.
A2000A (and some early B) KBDs come in dark beige small F-keys and DIN-plug.
A2000B KBDs come in dark beige with the standard layout/keys and DIN-plug.
A3000 KBDs come in slighly brighter beige standard layout DIN-plug, but a slighly different case.
CDTV KBDs share the case with the A3000, only in black and with PS/2-plug.
A4000 KBDs also have the newer case, a PS/2-plug and should be in white (but are most likely in varying shades of yellow :-( ).