Yes, a bodypaint or second skin is just a texturemap, usually with a pose MAT file to apply it automatically to a figure. If you want to limit things to Poser 5 and later, there are ways in which the new texture can be combined with a normal figure texture, using a third texturemap to control the switching. Otherwise, any skin showing in a second-skinned material zone has to be matched when the texture is made. Some stuff is distributed in formats such as .psd, which makes it easier for the user to make a combined texture.