I've seen 90*fittings on there. Ima guessing they changed the threading to accomodate that and put the tube seat at the bottom of the 90*. The 90s were a very tight fit to the M/C.
Nope. They actually had the inverted line threads cut into the engine side of the cylinder bore. I got one here, rebuilt in a box for him. I PM'd him , so I can send him pics.