That procedure SHOULD generally work, but some flanges will inevitably warp and result in leaks that could probably have been avoided by the slight margin of flexibility that a gasket gives you.I have a Pwerks catless down pipe and have NO gasket between the turbo and the downpipe.
2 machined surfaces should seal against each other
Believe it or not, back in the old days some of the MG racers used to run their T series engines with no head gaskets. They'd 'dry deck' the engines by plugging all passages from the head to the block and replacing them via external connections and the would lap the head to the blocks (for hours!) using valve grinding paste. Sounds a bit crazy, but it actually worked. Some of them still had the heads lift though, so the carefuk guys used a solid copper head gasket too.