It arrived (actually a few days ago, but I've been busy). Check it out, brand new in the original box!
Super cool. I can highly recommend Arcade Electronics as a seller. I still plan to make and post a printable replica.
No. Surprisingly, that isn't necessary. The relationship between two or more SIMMs (and not the sockets) is what prevents each SIMM from rotating. The socket holds the SIMM in place (even without the clips) so long as the SIMM isn't rotated.