So far nothing has worked, not a heat gun, not solvent, nothing. I think @day_tripper is right, it is thermally fused plastic. I looks so much like a sticker, because its got that slightly raised edge you can catch a fingernail on, but an exacto knife slid under the corner revealed it is plastic.
I wanted to spray paint a large stencil over the front, but my last attempt looked like crap (see my previous pic in this thread), so I may just find a sticker I like to cover it up. Too bad, I thought the M*A*S*H stencil would have looked cool. Thanks to all for your suggestions.