Interior of the starboard wall of the hangar bay of the Star Trek starship Enterprise studio model. Other than a hole in the wall, there is no other evidence of a mounting point for the original side light. The side light may very well have been created by inserting a Plexiglas rod into the hole from inside and attaching a blinking light onto the inboard end of the rod. Also of interest, notice how different the portholes and windows appear from the inside (and how you create a green window by slapping some green Plexiglas over the inside of the existing colorless window).