Good information, Edgar. Here is some additional information and a few corrections:
1) "Golden J" is a nick. The official name in company literature is simply 'Jubilee'. Its model designation was also 1205, but service manuals tacked on a 'J' for reference purposes.
2) The Olympia Ones, according to Tig21er (John), a longtime friendly Aerus (Electrolux) man since the '60s (having his start with his dad in the '50s), debuted in April 1979; which makes sense since it was closer to the 1980 Winter Olympics which was the reason for its namesake. '1978' must have been given in error at one point and after a while myth became fact. It actually had 3 model designations: 1401 (the same as the Super J except for the main body color); 1401-B (with 2 handles, wider wheels, and fins on the bumpers; and 1505 (short-lived; so named because it had the new Model PN-4A power nozzle with the shorter motor housing for getting under low furniture without scratching the hood).
3) There was a short-lived iteration of the Silverado that had the Olympia One horizontal handle (the Super J's was longer) & a finger grip and thinner wheels(?). These cleaners had the S_A serial affixes and were likely only sold for 6 months--one wonders if they'd found some overstock and decided to use it up.
They were brought back awhile after the introduction of the Diamond Jubilee because of motor problems, so its full run was 1982-85. Some have mentioned that the last ones had a different motor, so perhaps they were field testing the new DJ motors and used the Silverado to keep the DJ from getting the 'black eye' if it failed. Jimmy Martin or others would know for sure.
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As for dating the Model 1401-Bs here is a rough timeline for the Olympia One:
Model 1401: 1979 (April-September)
Model 1401-B: 1979-82
Model 1505: 1982