Trunk gap problem after new 1/4's

I still don’t understand how people think that any replacement panel will be a perfect fit to a 50+ year old car that didn’t have perfect gaps to begin with. The era these cars are from is not known for its careful, exacting construction. They were slapped together on an assembly line, and poor panel gaps and body tolerances were noted straight from the factory.

Factory tolerances were loose, 50 years of wear and tear, accidents, rust, and sag make every car even more unique, and there are tolerances on the replacement parts as well. It would be more strange if a replacement panel fit perfectly.