ray tracing RTRT solution proposition

I've been following some of the developments regarding the future of reshade when it comes to ray tracing games from reshade
the problem is there is no information regarding a meterial's reflectivity from reshade (only have a depth buffer)
what I am proposing is something that's already been done before in a different way, for the purpose of the proposition I would like to give it the name "RT mapping"
there are 3 known programs (TexMod (DX9), uMod(DX9) and resorep(DX11)) that perform texture replacement on the basis of a texturre hash
what they do is compare a texture's hash during runtime to allow it's replacement for modding
I believe reshade could use this as a basis to create "RT mapping": aka instead of replacing the texture/materials based on the hash value, only define it's reflectivity
obviously reflectivity will have to be defined (probably manually) for every surface by the moddev
data for each material's reflectivity can be saved into a list file with hash:reflectivity pairs

That won't be helpful, since there is no simple way to figure out which parts of an image where rendered with which material (not to mention that every game engine works differently).