Joe, one of the things Electrolux salesmen would offer to hard-sell customers was to sell them upgrades to their cleaners including new hoses, cords, attachments etc., and power nozzle retrofit. I've seen Models LX/LXI, E, E-A, S, and early F with power nozzle ports. Never seen an XXX but that's not to say it was never done!
The first models to officially have the power nozzle were the late Model F and Model R.