Re: Reply #7 (Serial Number)
You're correct that Z 12937 Z is the serial number. Interestingly, Electrolux Corp., now Aerus LLC, has used that same alphanumeric pattern—5 digits with 2 letter affixes—at least since 1937, when the Model 30 was introduced.
Btw, the Model 1205 "50th Jubilee" (nicknamed "Golden J") cleaner's serial affixes were Z & Z, so your Model 1401 Super J(ubilee) is likely a '75. The letters were not always used in order as evidenced by the fact that the prefix was changed to a K after the Z_Zs were finished. I don't think the suffixes always went in a-b-c order, either.
As for the motor having its own serial number it didn't. It may have been assigned a part number, though.