Nowadays Plain Enamel is custom-ordered by p'up makers ONLY. And AFAIK, only one wire maker is still willing to make a benzene-based enamel to produce PE like old times. This is the wire used by most PAF repro makers and it doesn't come cheap, that much I can tell you.
Copper wire is the same, it's the insulation type and thickness the variables that give the dialectric characteristics, together with the coil geometry (the way the wire is laid on the coil, TPL and tension) what gives a certain p'up a certain sound, vibe and/or behaviour.
So, knowing first-hand the industrial and production side of the equation, I believe more in my own knowledge than just taking your word for it.
So, do I know the answer FOR SURE? Of course not. But what I belìieve is that most likely IS the same PE. Why? Because it makes no sense economically and/or production-wise to spec for two different PE wires.
HTH,