After waiting some time (the guy I ordered them from was pretty slow), my new keyboards arrived!
I got three with part number 1391411, one built in 1990 and the other 1992. The third was built in 1996, and does not have a detachable cord. Very strange! Or maybe not.
I really like these keyboards! They both sound and feel great.

Took a while to get used to, but I feel like my typing speed and accuracy has increased a bit. A quick test showed 84 wpm, a slight improvement over previous results.
I tried painting one of them black, with pretty good results. I used vinyl paint, and hopefully it won't peel off or anything. Time will tell.
Some pictures:
This is the label of the one I painted. I managed to peel it off and reattach it after painting!

Action shot!
