I can't remember reading anything about gaps. In new car photos I've seen, gaps are somewhat irregular. Making gaps even between stampings on my car required extra work. Here's a couple photos after the metal shop gapped mine and they're pretty close, but worked well.
It's now at the painters who also did custom work in the past. Based on his shoebox Ford experience, he thought the fender to cowl valance, and fender to door gaps were too tight and moved the fenders forward just a bit while he's been working on it. He had it put together yesterday for one last test fit before painting. I'll see if he'll measure what it is now if it's still together.