In a PBR metal/roughness workflow, I know that all dielectrics are hard-coded to have 4% reflectivity at F0, and metals have a much wider range of 70%-100% reflectivity. It's important to use the correct reflectance values, but if I'm using images, then don't they already have the correct values? It would seem to me that creating procedural metals would require using online charts to get the correct values. For example, if I want to create a gold sphere, the values are (1.0,.76,.33), and I would enter these values in the color swatch to get gold.
However, if I have an image texture of gold, I would simply plug that into the Base Color socket and not concern myself with the reflectance values since it's an image of what I'm trying to create. Am I correct?
I've poured over countless web pages and .pdf documents about PBR, and I've found nothing that explains this.