It is my understanding that nForce2 boards with the latest C1/A1 stepping on the NB have "official" Barton 400mhz support. And, yes, I think that these latest nForce2 boards will simply be rebadged with the new marketing.
BTW, I'd be really surprised if my rev. 1.1 8RDA+ didn't work just fine with 400mhz Bartons, even if it isn't "official." I could be wrong, of course.