Keybar Issue

[Dan Jones]

Please check out the photo attached, I received some keybars from the late John Eickhoff many years ago. Two of them have markings that do not make sense. One has the serial number "1605" on the frame in a box marked Bodoni 3949. This keybar frame is hand-marked "3531" inside. The other one has a serial number "747?" on the frame with the last digit damaged so it is not readable. I put them on the keyboard to backwards engineer them to any known MCA. They fit the keyboard (one is for the right side and one is left) however, the keybuttons do not fit on top. It appears lugs at the bottom of the keybars are different. Any opinions? The one on the right in the picture works, the one on the left does not. It is a keyboard from 1968 designed for 15 x 17.