Nope. HDR on multi monitor setups doesn't work and I don't think it ever has. Funny, after years of playing I finally just turned it off yesterday; game looks better and runs quicker, should have done it a long time ago.
Edit: I should add that it can be made to work by matching your centre viewport to your total resolution but then your view will render across all screens, and your MFCDs will display on top of the game image. As much as I like the HDR effect (on one monitor), especially with PeterP's excellent mod, it's better to just turn it off. Believe me, search "HDR multi monitor", it's been like this for years :(