I agree more or less. But natural weight depends on age as well so it's a very relative question. Loma is a bit older so i don't see him growing that much anymore. Same goes with Golovkin. He's 34 years old, his natural weight is 160. He moves to 168 because he is that good, not because he has to. If you compare him to 154 pounders and how much Charlo bros, Canelo or Trout are cutting, golovkin should be a JMW - he walks lighter than those guys.
Loma said his naturall weight is 145-148 lb (65-67 kg). https://www.youtube.com/watch?v=7-JKO03mfvQ 35:10