The way i see it, if someone is trying to sell you a Peugeot with cottered cranks and claiming its a PX-10, It isn't.
Although I'm sure in some market, at some time, A PX-10 variant had cottered cranks.
And starting in the 70s you could order custom built PX-10s from a shop. If you requested I am sure they would put some cotters in your cranks.