Its not auto trim but it is stainless, I restored my 1967 triumph front and rear fenders. They were bent, cracked, dented and just a mess. I made a buck out of oak and with a lot of easy tapping with a plastic hammer and home made plastic wedge's and a shot bag I managed to take the dents out. Then I sanded them with 220, 500,600,1000 then I buffed them with my pedestal buffer, from red to white. It takes super patience and if you get a little riled put it down. The best thing I did was make the oak buck with the same form as the fender that way I had a good form to get the fender back to its shape. Do not hit the stainless to hard, it stretches really easy and then you will have a mess. You can use a cut up plastic squeegee taped to the part so when you tap it will not dent or stretch the part. If it stretches I used a stud gun with a nose in it for that, heat the area easy and spray it with water from a bottle, keep it localized to the area that you want to shrink, you can also use a pencil torch but be careful. The cracked area I had stainless welded from a friend of mine. I ground down the weld then slowly hammered the fender with a small curved body hammer on another oak buck then sand sand sand and polish.
It takes a lot of time and don't rush think about each strike. plastic hammers, thick leather belts, plastic squeegees all are your friends.