Quote - Why would you need the UV Map for? Just go into the textures from the original model or clothing and Paint or design over that?

Because that makes your work derivative, which means that you are infringing on the copyright of the original creator. Even if what you end up selling has no pixels in common with the original. Plus, pragmatically, if you want something more detailed than the original (adding stripes, for example), you need the UV-mapping to be accurate.