I scraped the side of my 5er (smooth fiberglass side) on a post in a fuel station in Marysville, about 3' long and a foot high. l
The RV dealer-recommended place said $1,500 to *try* to put in a replacement sheet and fair it in to make it look like it hadn't happened. But there were no guarantees and they were doubtful they could do it.
Since it was between a storage bin and the heater, I chose to have them put in the new piece and then put a visible seam horizontally where new meets old. The seam runs from the bin to the heater. If you didn't know it, you'd think it belongs there. They also had to replace the bottom seal along the side. Cost - $900.
Fiber repair ain't cheap.
DBF