If you want an M with the old square silver IBM logo in the upper right, here it is. I've got a 1390120 made one week before, the one without the CAPS/SCROLL/NUM Lock lights, it has a weird CTRL scan signal that has to be specially mapped, but I think that this one which is for sale is has the "normal" CTRL characters. Worth noting that it comes with the original cable, these all had black cables AFAIK, but a number of the ones I've seen have been replaced with newer cables. It's tough to find an M older than this!
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290284807157&ssPageName=ADME:B:WNA:US:1123