Hi Alkay, If the stuff going through a printer doesn't hold ink or toner then it won't work. In saying that I do remember when at school last century some of the teachers had what looked like pages printed onto clear OHP (overhead projector) slides which looked like some thin acrylic plastic stuff and presume they had been simply used in a photocopier to lay down the image. If you can get your hands on some OHP clear sheets and run it through a laser printer that might work however it doesn't have the sticky backing or softer vinyl texture of contact paper.

Maybe a compromise might be to use transfer decal waterslide paper, spray it with some clear acrylic, cut it out slightly bigger than the headstock then soak and apply. Once sufficiently dried out, trim and then apply the clear contact sheet over the top, remembering to trim that as well including the tuner holes.

Cheers, Waz