due to owners updating their coachs striping is rarely a sign of the vintage. certain feaures will opoint to a year range. Does it have front wrap around windows? Do the two pieces of trim that the stripes are laid in stop in the middle of th trailer? DOes the entry doo have a window in it? Are the windows framed in alumimum? Do they that square or round corners?
The answers to these questions will get you an idea of what year the trailer is. To know the model, you will need to look at the name plate on the unit itself. It should be to the right of the entry door.
If you are interested in the trailer and it ooks like it is not used, ask! the current owners may be considering selling it and just have not done it yet. They might also give you a good deal due to it not being used any more. Here is a link to many models up to 1976. if you stuby the photos you will start to see the differnences by series of model years. Also you may be able to identify the model by window layout.
Have fun and get us some more info so we can help you