If your subD model is modeled to prevent UV sliding it should not matter. If not subdivide once and texture that version. But use the unsmoothed version for rigging and rendering.
Writing and optimizing efficient HLSL shaders for games. Complex character rigging (especially mechanical, where there's less skinned animation and more rotation/sliding)
Looks great. The design reminds me (slightly) of Human Revolution's machine pistol. What's with the pinching on the corners of the oblong inset for the stock to slide back into?