Only if the exhaust flange and the cylinder are flat. Almost without exception the welded flange on the pipe will be warped to some degree by the welding process.
You can check yours by painting the gasket surface of the flange with magic marker or machinist die and rubbing it on sandpaper laying on a sheet of glass. You'll quickly see where the high and low spots are. Keep sanding until the surface is exactly flat.
Same for the exhaust port gasket surface on the cylinder though they are usually pretty good.
If you get the flange nice and uniform a hard gasket, aluminum or copper will work but you'll need to make sure you're starting with a good mating surface.
Good luck.
Tom