And you would be correct. But you will never have a controller give you both. It will either be vis on the ATIS and the subject never mentioned again. Or the approach controller/tower will give you a RVR value they won't give you both.
I will add this only works for controlled aiports if you ever start operating into Information service airports things sometimes get a bit weird you should get special briefings before you do and at that point if its not mentioned you can ask the question to your Chief pilot. technically you can just take the RVR but they may have different ideas.