if this is just a swap out, of DDR3 for DDR4, and the board has always supported DDR4 like ATI claimed, then theres no real reason this should be a huge drastic thing for them...
get the memory, put it onto X1900's they already have, call them X1950s, pack em, ship em and wait for the money to fall in thier bank accounts, haha.

its not like this a huge change, so they probably already have a few of these laying around, ready for the big time review sites (anandtech, tomshardware and such)