I'm at work and don't have Greyman's book handy, but give that a look. The actual name of the lock is Rielda (the bars on the left and right are decoration). If I recall correctly, these things can be rekeyed in the field using a key (like the Smartkey or now Securekey) and were the original locks to do that. I can't remember how they work, but if I had to venture a guess; that cutout on the key is probably not present on the "changer" keys. Then again, I may be totally off and thinking of the wrong lock, but "Rielda" is definitely the right name. Good luck
