No, the Arca Swiss-type plates for the RRS BH-40 (and ballheads from Kirk, Markins, Acratech, and a host of other excellent brands) do not fit on the Manfrotto RC2 clamp. Manfrotto uses their own plate designs, and they're not even compatible within the brand, let alone outside the brand. That's one reason I switched from Manfrotto to AS-type plates/clamps.
While some of the Manfrotto heads can be converted to an AS-type clamp with the Wimberley C-12, the 496RC2 isn't one of them. You could replace the monopod head (with an RRS monopod head, for example, but a Manfrotto 234 tilt head with a Wimberley C-12 is what I used before getting the RRS setup to hold a 600 II), or get the Kirk 'adapter' (link) that has an RC2 compatible base under an AS-type clamp.
See, this is why I like this Forum, had no idea, now I do.
I generally don't try to work all this stuff out, so I go all RRS gear and I'm done, but it's just great that some people (neuro) do take the time to work it all out, invaluable info, Thanks Neuro as always.
+1. It's one of the most enjoyable forums I've been involved with. With folk like Neuro and Mt Spokane Photography providing excellent feedback, my poor little brain is churning away with ideas
And others throwing in feedback, such as jonathan7007 and Dianoda, gives me food for thought. Thanks to all who have responded. Much appreciated