Go and ferret and you'll be able to answer your own question.
As said, a number of Alps pots use/used conductive plastic. And just because one goes noisey, it hardly equates to it not being conductive plastic. Of course it could have been a fake and who's to say what the construction might have been - without disassembling it.
Didn't find much on it in 5 minutes but it is apparent that conductive polymers exist that do indeed conduct without metallisation.
The Alps Blue just went out like any ordinary pot. The wiper went noisy, you could alleviate it a bit by repeated back and forth motion. Just like a cheap metal pot.
I ordered another one to replace it. It was exactly the same externally. It was in a Beard amp originally.
The Penny & Giles pots were expensive but they exuded quality Alps Blue don't posses.
Alps do make some very high quality pots. I own one and it is fairly insane.
I try to use "passive pre" but then someone will ask, pre to what?
I think the ALPS Blue can work very well but it needs to be in a proper active preamp with a buffer before it and buffer or gain stage after it. As a passive pre I find it a little muddy.
Decks: Salvation + London Reference | 301 + Ortofon 2M Mono SE Digital & Preamp: Lindemann Musicbook SOURCE Amplifier: Lindemann Musicbook POWER 500 Speakers: Bastanis Sagarmatha Duo with with twin 15" baffle-less bass drivers per side | MarkaudioSOTA Viotti Tower
And traditionally, what preceded the power amplifier? Volume control (sometimes a buffer), tone controls, switching, and a phono equaliser, not needed with ceramic cartridges.
The advent of cd popularised the idea of two pots in a box.
It did exist before then though. I think PS Audio pioneered (or was one) the idea of having a stand alone switching unit with volume control, along with a separate phono stage and power amplifier. They have a different approach to signal attenuation now. It's done now by manipulating the power amp's sensitivity.
"Can I have a flake in that and some monkey's blood please - mista."