As i understand it´s just a naming convention and probably has to do some with how the shaders compiles and optimize. but in the end everything is just bytes.
I Dx11, it´s not named F/B/I and just SetConstantBuffer. And thats also why i assume it´s the same here and more of a naming convention than anything.
and if you read on msdn, there is no real hints that it would be anydiffrent.