New entry from eBay:
412-2, S/N 319, deep chassis, no bottom plate, black glued-on embossed data plate. Considering the low serial number, and that the embossed data plate didn't appear on all 412s until somewhere around S/N 700, I have to assume that the 412-2 models either had their own serial number (rather nonsensical, since they use the same chassis), or that the 412-2 data plates were glued over the original ink-stamped 412 "Basic Chassis" data plates. I've emailed the seller to see if they will provide me the motor date.
412-2, S/N 319, deep chassis, no bottom plate, black glued-on embossed data plate. Considering the low serial number, and that the embossed data plate didn't appear on all 412s until somewhere around S/N 700, I have to assume that the 412-2 models either had their own serial number (rather nonsensical, since they use the same chassis), or that the 412-2 data plates were glued over the original ink-stamped 412 "Basic Chassis" data plates. I've emailed the seller to see if they will provide me the motor date.