Drew,
I have a Classic LQ trailer, the roof part you are referencing is aluminum. Airparts has the bright aluminum. You would need to give them measurements and they will cut it, I do not recall if they can do anything else. I would suggest calling and speaking to them. A competent sheet metal shop should have a slip roller.
https://www.airpartsinc.com/208_2024...t_and_Coil.htm