the grouping names and objects will be different, but all texture coordinates and materials will be the same unless you apply a new material or a new uv map modifier. As long as you use the grab tool in your material editor instead of the apply tool and you dont add any uv stack modifiers to your object, your mapping and textures should still work exactly as they did before you regrouped it. However, if you add or remove any geometry (scaling is ok, and so are morphs) your uv data will be out of range and you will have to remap the object.