RenderAssignMaterialToObjects and RenderAssignMaterialToLayersOfObjects are new commands of Rhino 7. RenderAssignMaterialToLayersOfObjects prompts first for material name or ID. Then it prompts for objects. RenderAssignMaterialToLayer is older command. It has similar sequence of prompts. For no apparent reason the sequence of prompts is reversed in the RenderAssignMaterialToObjects. In my opinion, the first prompt of the RenderAssignMaterialToObjects should also ask for material name or ID.