Power Nozzles!
Fred, I also have a PN-2 with a blue sheath and pigtail connector. I haven't yet posted a photo of it because I haven't polished it up as of yet.
From my understanding, this is the progression of the Lux PNs from the earliest up until the Golden J...by 1975, PNs were "de rigueur" with a vacuum cleaner purchase due to the era of the "shag carpet":
1959: The upper-tier Model AF and lower-tier Model R were offered with a PN plug-in port. The matching PN-1 was offered in white with gray bumper to match the AF and the R. This was the first PN Electrolux offered. Connection from vacuum to PN was achieved through a wire which was "zip clipped" to the vacuum hose.
1960: The upper-tier, aqua-colored Model G was introduced, whilst the lower-tier Model R was continued in its original colors. The PN-1 was offered with the G in the same body color as it was with the AF, but the rubber bumper was aqua.
1963: The Model R was discontinued, with the Model L replacing it. Model L was white with aqua rubber bumpers, which matched the bumper on the PN-1 sold with the aqua G. The aqua Model G would run until 1967. PNs did not change from '63 until '67.
1967: Model G was offered in bronze, as was the Model L. PN-1 remained the same, yet the only difference was the changing of the bumper color to match its concurrently offered machines.
Up to this point, it seems that Electrolux knew that it would have a bit of difficulty selling its "newfangled" power nozzle to people...therefore, they made it so that any machine they sold between '59 and '68 could accommodate the same PN, and in a color that would match by merely changing the rubber bumper.
When the 1205 was introduced with the '68 Model L, it's obvious that they threw that idea to the wayside! It was then that Sara Lee had bought out Electrolux. The PN-1 had a blue body with blue sheath, to match the new 1205 and the blue L.
As for the PN-2, I guess it was introduced around 1972. My 1974 Model L was purchased with a PN-2 with pigtail connector. However, I know that the Golden J was sold with a PN-4...and it was a direct-connect hose. But I do contend that my mom's '77 Super J had a PN-2...which was really a PN-4...the only difference being the sheath color.