Having them in the guitar would make a difference, I would expect resistance to slightly up since there's more wire n components n stuff that the meter is reading.
I believe they were labelled "P22" because there's a difference with polarity, so they work with the piezo. I remember Juka had all sorts of fun trying to find compatible replacements for his P22, but I also remember someone else having no problems at all...
It's quite possible I have 57/08s (I bought them 2nd hand), and I was under the impression the changeover came more later on in the year. Either way it doesn't bother me, they're both great pickups.
I'm changing out the covered 53/10s in mine to these uncovered P22s, so I guess I'd better record some before and after clips just to check.
I've also been driving myself crazy trying to work out the switching I'm going to do, since PRS recommend moving the "hot" on the bridge and "ground" on the neck for coil tapping. Well, I want to be able to select which coil/s are active, so fun times wiring are coming up...
