I don't think pineapple grenades had body markings that were painted. They did have markings moulded in and the yellow band painted on the neck.
What I do for dummy grenades is fill the hole with epoxy, sand flush, and paint the body. Of course, the fuses are wrong for the pineapple and lemon variety as they are all baseball type. If I had stencils, I'd mark accordingly. I did see some baseball fuses that were not the blue training variety but the green frag variety at the gunshow.