OK, what happened is the car was registered and licensed in California. When the car went into storage, the registration expired. To get the titled changed, the guy who bought it went to the DMV and paid the use tax and registration, then they issued temporary registration, the red tag on the window with an expiration date. Usually this is done when the car was purchased but not yet smogged. California, being the accommodating state that it is....takes the use tax money and registration money from you and will issue you temp registration for you to get the car smogged. Their biggest goal is to get your money. So, I guess the temporary registration was left on the car and the yearly registration wasn't done. This happens a lot when someone buys a car and then wants to flip it.
California cars are usually pretty rust free. Although up North they do get a lot of rain. If the car was garaged, it will be evident. Check around the rear window and around the wheels. These are the area's they usually show signs of rust. But chances are you've got a solid car. Always figure the engine and transmission need to be rebuilt. And always allow for brakes. Remember, you're getting a very old car by most peoples standards. Expect to put money into it. Actually, I've only driven my T/A about 150 miles in two years. It's currently on blocks because the shop that installed the cam two years ago didn't torque the pump eccentric bolt and it came loose (at least that's my diagnosis at this point) so I'm tearing the front of the engine down to fix it. Also, assume the mechanics don't know crap about these cars.....because they don't. Everything is done in a hurry nowadays. No mechanic will ever touch my car again...I only let accountants near it now!!!