There are actually different Hatori part#'s for the Aurora and Atlanta headers:

I have a couple of the 755 headers which is the YS Cosmos/Aurora header and a 724 OS Atlanta header...Holding them up I have a tough time seeing how it would matter much...The rise appears to be the same and the Aurora might hook back a degree or two more but not very much...I'm going to articulate all my headers anyway so the slight difference won't even matter...

I say if you got one or the other you should be good to go...

My .02...

Chuck