Is it possible in Zbrush ?
Yes. There’s the ZProject brush. With Draw>Rgb turned on it will project polypaint, which can then be converted to a texture. Another option if the meshes are very similar in size and shape is to append the new mesh to the old one as a subtool and then use Tool>SubTool>Project All. (Again, with Draw>Rgb active.)
Aurick, thank you for that. You just saved me a TON of work! 