I'm still getting used to/ learning about T-birds so the best answer that I can give at this point is what the seller told me:
The pickups are Gibson pickups but changed to chrome pickup covers and rings.
The bridge was changed to a Gibson mixed black/chrome.
The tuners were changed to chrome ones and a bass extender added.
For my own edification, I'll be pulling the pups to get the exact make/ model soon as well as ID'ing all of the other parts/ add-ons, etc. I like to document the whole instrument's parts, like I've done with all other used instruments that I've picked up over the years. How can one GAS for something new and different if you don't know exactly what you don't have yet
In the meantime, I've been enjoying the amazing sounds that the T-bird is adding to my bag of tricks