What have I got here? Magnum 5.9 Flex plate identification

So i ordered up a stock weighted Magnum flex plate from Rock Auto since according to MagnumSwap.com, folks had used these successfully with the 904...or thats how I interpreted what I read.

Well, it showed up today and it's the exact diameter of the B&M unit that is used with the 727. :banghead:

Umm... So is that pn 10241 B&M flex plate the ONLY way to mate a 904 up with a Magnum?!!

Somebody else must have done done this before...right?