Hi Teisco,
I think historically, vintage guitars have held value quite well. Here is a graph representing the appreciation of primo Fenders, Gibsons and Martins over a decade or so.
 
Obviously, Teiscos are not Fenders and Gibsons, but I think the general trend probably holds, it's just the magnitude of the values that are different. Of course, all this really depends on the Teisco models you are considering. Many of the lower-end models will never appreciate a great deal because of inherent limitations in playability and the huge number that are available. However, I think a collector can have reasonable appreciation expectations for more desired and less common models like the Spec 5, Shark Fin, Monkey Grip, etc.