Mine's not like that at all.
There's no telling what you'll get and every machine's particular fit is a unique meeting of irregularities between the head and the pipe.
Honestly, I've considered doing what some Triumph owners did with their later-model heads that used an interference fit--add stubs to the exhaust port to fit earlier-model Triumph clamp-on pipes. There are a lot of kits available to do this to the triumph heads, and those could be a basis, or I could find someone to do the AL welding straight to the head. Think I know a guy...
Could have my current header modded to fit pretty easily on that arrangement, too. I really detest the process of mounting and unmounting the stock header. Always have, always will. My exhaust springs were a pretty good middle ground, though. They're what's kept me from doing anything more drastic.
Using something that's easy and repeatable is much nicer than a magic combination of shims and goo. My Matchless has thread-on collars, and I almost giggle when I take the pipes off. It's just too easy. It should not be something you have to wonder about.
I know some headers and heads don't have that issue. But some do.