These were lightly equipped bikes. Chrome rims, whitewall tires, and the deluxe teardrop rear reflector. The Miss Teen is a rare model but not particularly collectable. From a financial standpoint not worth doing resto work on it. From a relationship standpoint, hey, how much do you like her? Couldn't hurt to throw some love at this bike. You are likely going to be out of luck finding the decal for the guard. As a last-ditch sort of thing you could always throw the guard on a xerox machine, get a hard copy of the size and font of the Miss Teen bit for future reference, and then hand-letter it in after you repaint the guard. Or you could (with your sweetie's permission) go on the hunt for a mo' better bike for her. Because once you throw paint on one of these it usually just look like a repainted bike.
Cheers, Geoff