1200M

This is a two-parter: 1) Can you tell me what the letters that are stamped into the rear top left of cornwall I (when viewed from behind) correlate to? I have a set of 1978 cornwalls that have: OD A E F And I have a third 1978 cornwall that has: A M O I'm particularly interested in learning if these codes correlate to something about the model of the "AMO" speaker, which is somewhat unusual, and I'm trying to learn more about. The "AMO" cornwall I have has a standard looking three-port 1978 motorboard, the tag is very worn but says cornwall, and the stamped serial number looks normal for this model and year (16S80). It has a square magnet k-33-e woofer, and type B crossover. What makes it unusual is that it has handles recessed into the sides, much like those that later came in the CP-1, although these handles are two-part, with a black cup that recesses into the speaker, and the actual handle is a separate polished metal piece with a black and white "klipsch" inlaid into it. In addition, the speaker has metal corner protectors. The cabinet itself is black. 2) Did speakers like this ever come out of the factory in 1978, or are the handles, black finish, and metal corner protectors modifications that the speaker received later? Unfortunately, the tag is too warn to see any information about the factory finish.