You guys might want to consider dyeing the bodies as well. RIT Demore would work perfectly to get that darker skintone.
Definitely. Acrylic paintwash will also stain that rubber pretty easily to -- I've done it to Indy, German Mechanic and Belloq. I haven't tried dye on a body. Do you have to put the whole body into the boiling water? Seems tough to control -- once you get too dark, there's no going back.
Anyway, got to get a head first to see the color.