getting ready to buy an 02 GT.. but it's a California car.. need help on smog pump

That depends. if it has been taking care of, then no. Really, with 4.6, all you need is like keep up with basic maintenace, and it'll go 1/4million miles befor showing any real sign of age...

If you drive like rest of us, may be 150 befor starts to see some miner issue...