there is an faq full of this sort of information, try looking there.
generally most of kurts stangs were either vitnage(stock mostly) and then the japs had jb humbuckers in the bridge with a stock single( i believe but im not certain)
he had maybe 1 or 2 mustangs made by fender us, i know one of them was red and he almost never played it and i want to say it had a jb in the bridge and a texas special in the neck.