I did not label mine and no mention of such a label ever came up in the inspection. Some of the guys that have Air Force paint schemes have "emergency release" or similar painted on the outside. But in looking at Doug Reeves' "Flash" http://www.vansairforce.net/virtual_tour_n617ar.htm I don't see any on his. One of the pictures shows his interior latch too and it appears to be unlabeled. There are several Pictures of planes in the model specific area so you may want to surf that area for ideas. I have never seen a Cessna with "Door Latch" emblazoned on the area of the door latch (or maybe I never noticed ) You could label the pull out handle with a stick on label that has an arrow and note saying "Open" and point the arrow in the direction of movement when the handle opens. Once inspected sometimes these things fall off (unintentionally of course)
My DAR wanted me to label the outside of the latch for the TU canopy because if I passed out from the heat or whatever, I could be rescued. I dutifully put on three labels because that's what it seemed to take to explain it. Then I realized that if the top safety catch is turned to "safe" all the rest is useless. I am considering putting a little handle for that on the outside the way it is on the slider, but haven't done it yet. Food for thought.
) You could label the pull out handle with a stick on label that has an arrow and note saying "Open" and point the arrow in the direction of movement when the handle opens. Once inspected sometimes these things fall off (unintentionally of course) 
