Brainstorming - How To Repair Holes In Lower Side of Trailer

Howdy:
We recently acquired a 1941 (?) homebuilt teardrop from out in Nevada. Unfortunately we found a bondo repair that had been painted over and over
on one side, lower rear of trailer. I imagine its from water damage. The repair/holes are over 2 feet long. The trailer has a buzillion aircraft rivets holding it together...a few of the old timers we know who looked at it thought that it was built by someone in the airplane industry. Want to avoid removing and replacing the whole side of the trailer, as I am afraid the new side will not match the other side. My thoughts were leaning towards riveting a strip of aluminum over the lower back area, on both sides to match...any thoughts?
Margaret and Steve
We recently acquired a 1941 (?) homebuilt teardrop from out in Nevada. Unfortunately we found a bondo repair that had been painted over and over

Margaret and Steve