Maybe, but I don't think that tells very much about their strength,
I think some of the differences in opinion in powerscaling come from mainly two different views of haki, viewing haki like a power level, ki, that can be trained to get stronger, or vieweing haki based on the techniques it has, like saying someone with acoc always beats someone with only armament in strength,
Me I think haki is a thing you can train, the techniques are nice, but you don't need anything other than basic haki to be able to best anybody, if you train it enough, whether you have conqueror's haki or not,
So whether Mihawk or Ryuma have conqueror's haki or they don't, I don't think it changes their strength, because if they have even just armament, that means they just trained that and got it to be strong enough to do what they did,