Yes, you do. I don't know what the designers were thinking, but yes, you do have to open it up so that you can rotate wire end first into the servo slot. Those two root ribs need to be opened up so that you can do that. You keep the the slot where it goes in the same, but inside you have to make it open enough for the servo to rotate into position. Remember, the servo rails will raise the servo by about 1/4 inch.