Sure. It actually makes more sense when you read it.
For lizardfolk, the conversion guide suggests that a regular "lizardfolk" would use the "scout" stablock (and, I presume, any other humanoid NPC block, for various humanoid-lizardfolk.
The MM page for Lizardfolk explicitly states that these are Lizardfolk who live in jungles suffused with primal magic or who have undergone rites to enhance themselves with a connection to the elemental plane of earth, and are the Lizardfolk Sovereign and Lizardfolk Geomancer statblock.