Sorry, I don't understand the question. What is "SG SS apple watch".
If SG is "space gray", that color only comes on the aluminum sport watch. The color is dyed into the surface when the watch is anodized. No DLC coating on the aluminum.
The stainless steel watch comes in space black (not gray). The black color is DLC.
Yeah, I expect the Space Grey Sport to get scratched up quite a bit. The Space Black steel Watch should be highly scratch resistant, if they did the DLC as they should.