I'm the Wiz, and nobody beats me!
had to go wipe the dirt off and take a look again. must be electroforged. just the seat mast.
To my eyes it looks like a nice fillet brazed joint, like the downtube joint. Dark paint doesn't make it easy. Interesting piece and I'll have to check the numbers out, but I think that's the lowest one so far that has shown up with the EF shell.