I think the right lead is a bit outdated. Having your strong side closest to your opponent isn't always a good idea, especially if you face off against an opponent trained in limb destruction. If you lose your power side, you're pretty much done for.
Jack Dempsey: "What would happen if a year-old baby fell from a fourth-floor window onto the head of a burly truck driver, standing on the sidewalk?
It's practically certain that the truckman would be knocked unconscious. He might die of brain concussion or a broken neck.
Even an innocent little baby can become a dangerous missile when its bodyweight is set into fast motion."