The rank insignia on the Colonel's right shoulder is upside down. The eagle's head should be toward the wearer's head. The left shoulder is correct.
Little Joe is smaller in weight size and strength than oldest brother Adam. When he goes to rescue Adam who is gravely wounded and unconscious he lifts him and cradles him as if he were a smaller person He would be physically incapable of carrying that weight in that manner.
When Ben Cartwright (Lorne Greene) is being shot at and running back to the rock cover, you can clearly hear him or someone yell "cut" as he arrives.