BIG EDIT
I just noticed you wrote SG. No, no polish is going to do anything at all for the PVD-coated stainless steel bands. You will probably wind up changing the way the area you polish looks compared to the rest of the band. You may even wind up removing some of the SG PVD coating. Either way, you're going to make the phone look a lot worse. You can't polish the PVC coating. The best you can do for SG is try to color it with a Sharpie.
What I wrote earlier is only true for the polished stainless steel finish:
No polish is going to remove anything more than light superficial scratches. If you can feel it with a fingernail when you slide your fingernail over the scratch, it's just going to make things bright(er). And obviously no polish is going to remove dents (you said you dropped it).
If you use any polish, be very careful not to get the polish into the speaker grills, Lightning port or openings around the three buttons.