Welcome to Vacuumland. You have an awesome set of classic Electroluxes there.
The Model 1401 Super J was introduced in October 1975 and was succeeded by the Model 1401 Olympia One in April 1979. Its honey gold color was popular in the 1970s in appliances, glassware, and home furnishings. In case you didn't know, its predecessor, the Model 1205 Jubilee, was painted the same color but was shorter as it contained the smaller conventional motor.
Fyi, the hose pictured is not original. The first ones were white with triple tracers of teal, gold, & teal. The second version was harvest gold with triple tracers of teal, white, & teal. Also, in case you're interested in getting the rest of the tools they're ivory-colored.
Regarding the serial number affixes of the problematic armatures that had been outsourced after a fire in one of Electrolux Corporation's factories, they were K_S. That likely wouldn't be a problem even if yours contained those letters, though, because Electrolux changed them out for customers as they were brought in for repairs.
If you have some extra time, think about polishing your PN-4 power nozzles, so they have a mirror-like finish and polish the Super Js to restore their luster.
The E-2000 (E for Electronic display) was brought to the U.S. in 1985 when its Electrolux company and the Canadian one merged; but it was renamed the Hi-Tech 2100. It had many other iterations in terms of motor changes and color changes that were indicated by different model numbers and labels. Aerus's current Lux Legacy is basically an E-2000 with the onboard tool caddy on attached to its top.
I really like the styling of the AP (all plastic) cleaners. The ends remind me of the fishtail Coca-Cola sign.