The currency conversion coming with Mists of Pandaria is going to happen in three stages, and this is how we plan for it to progress:
With Patch 5.0.4 on August 28
With Mists of Pandaria on September 25
With Mists of Pandaria, Patch 5.1
Rank you can't earn Valor or Conquest again till MoP comes out. And I can't see them taking it away from regular BG's either in all honesty, especially since unlike with the VP, there hasn't been a new mention of an alternate way to gain Conquest in the expansion.
I was referring to whether-or-not we'll receive conquest points per regular bg win after September 25 or 5.1, like we do now. I was not referring to between August 28 and September 25. I'm hoping we still get the 50 conquest per win after September 25.
Which is why the answer is should but we'll know for sure in a month.