Identifying Fender pickups can be challenging. Pickup specifications modified and there’s not enough documentation regarding older pickups and their corresponding guitars.
Nonetheless, a few methods can help identify pickups.
By year: If you know the year of your guitar (and the pickups have never been replaced) then look up the guitar’s documentation.
By model: Review the guitar’s charts by year or by model. If the year is unknown, then the model charts can be helpful.
By inspection: Some pickups have the brand name, the model number, and even serial numbers. You might need to remove the pickup to find these markings — and even then it’s not positive they’ll be there. However, it’s worth a shot if the other techniques don’t work.
By ohm readings: Some charts match ohm readings to specific pickups. Of course, you’ll need an ohm reader to do this.