I did that exact thing with my first Tempest restore. Sometimes the artwork comes off, but there is a thin layer of clear plastic still stuck to the panel. I think it's a clear laminate. You will find that it's stuck to the panel with adhesive. The panels were originally painted black, so just make sure you've removed ALL adhesive and only have black paint left.
Here's my web page showing what I did (picutres below):
http://home.comcast.net/~dark.paladin/tempest/page4.htmBrian's website has a pictorial:
http://www.rgvac.com/restoration.asp?projid=19Step one, remove all adhesive down to paint/metal:

Step two, epoxy metal scraps to cover any holes you don't need from the back side:

Step three, sand top of panel and add bondo. Sand again until top is smooth, then apply primer:

Step four, paint panel the same color as your overlay just in case the edges show, and apply overlay:
