[johnmeyer]

Once the HDR still or video has been created, it is just pixels, like any other video. Yes, it has a certain "look" because of the gamma mapping, but I don't think the denoiser would "care" about how those noise pixels got there.

The only thing I can think of that might be a little different is that HDR photos and videos seldom have any totally black areas because the overexposed image (which gets mixed with the underexposed image to achieve the HDR effect) provides detail in areas that would otherwise be black. Therefore, if any of the denoisers include algorithms for denoising near-black areas more aggressively, that feature might want to be turned off or diminished.