There is no lens profile for the Canon 500mm F4 IS (Mark I) in ACR/LR. This seems strange since this is a very popular supertelephoto lens. Both the 400 F2.8 and 600 F4 are supported. I doubt that the lens is flawless and doesn't need a profile.
Does anyone know of a could 3rd party profile? I have been using the 600mm F4 profile.