The adhesive won't hurt the swingarm? It won't mess with whatever coating is on it?
The adhesive is already on there... you just want to get it off without doing damage... your swingarm is tough. I imagine it's probably powder coated or otherwise treated... be a little careful with the heat gun, but otherwise you should be fine. And like I said some solvent afterwards should clean it up, and that won't hurt the swingarm either. If this were on your paint we might need to be a little more careful, but you should be all set.