Sorry I haven't read every post, but has it been mentioned yet that the originals might be welded?
Better find out before trying to melt them off!

Yes it is usually obvious to an experienced eye, but I don't know how experienced our OP is.

TIG welded is very common, maybe even the predominant method? I don't know why, seems crazy to me -- IMHO the only reason to TIG them is if you don't know how to braze. Brass brazing is so GD fast, and 100% reliable.

Remember to braze the post part to the base part, if they're separate pieces of metal, as Mafac (and clones thereof) were. This adds something like one second per boss to the process, since it's already hot. Mafac style are swaged together, but not well enough to be reliable; they need at least a tiny dab of braze to be perfectly invincible.

Mark B in Seattle