Ditto with the above, you should be ok. I take scratches out of cars everyday for dealerships. When I come across one where the paint is dull, always my luck the thing is black, I start out with my wool pad and buffing compound which is a little more aggressive than the microfinish. Of course the wool pad is an aggressive pad itself. I only go to a heavier compound if the milder compound is not working.
Then go back with a microfinish compound and finishing foam pad to take out the swirls.
I'd start with a 2 x 2 ft section first to see what going to work before doing the whole car.
Oh, I use a DeWalt buffer, costs almost $300 though, but never go over 1,000 rpm though.