Quarter panel skins 66 coupe

I have began the removal of the old quarter and wheel housings. I have purchased my skin from Mustangs Unlimited... The skins fit is great but the contour lines are not sharp,,,they are kind of rounded were the skin wraps the trunk,door jamb, and top body line,,,does anyone know if this is normal and do you have to shape the skin to make them sharp lines...Following the removal and installation instructions from mustangs monthly how to forum and their skin looks sharp defined lines and not sort of rounded....