Question about identifying pickups

Varies wildly depending on the guitar and the pickups. Looking at baseplates can help. Not all pickups are labeled, but after market pickups usually have some sort of label or stamp. Alternate pickup characteristics are possible, too... brass vs. steel baseplate, on an uncovered humbucker you can usually see enough of the magnet to know if it is alnico or ceramic, etc.

You can look at the wiring, too. Most home jobs will be obviously different on the solder joints. And even with good soldering technique, there are sometimes signs, like if the grounds are wired up in a different place, if there's extra wire left on there (in case they get pulled and put in a different guitar), or some layout stuff that is uncharacteristic for that given brand. I've very rarely been fooled by soldering done after it leaves the factory.

Most of the time you don't know what you're looking for until you see it, though.

Oooh, okay. For some reason I thought we were talking humbuckers... not sure how I got that in my head. I'd have to see them to know. There could be signs. You can usually see the wire type on the neck pickups, and on the bridge the color of the string might change or something. Sometimes they're marked on the bottom, but Fender style pickups are less likely to be marked. Plastic wire vs. cloth could be something to look for as well.

Easy enough to pull up the control plate. I'd start there.