Depending on where/when it was made the Squire will have a different body wood some Alder/Agathis,some Ply -as long as it resonates well unplugged and you like the feel it's worth the expense of the pup swap.

Anyway,ask in the shop with the best repairman in town to get an opinion on who uses what locally -see if they've got any makers stickers up,they may be biased,perhaps you might get to play a guitar with simlar pups.

http://www.guitarnuts.com check out the wiring section.

Familiarise yourself with standard strat diagrams.