Quote Originally Posted by thebanana
Both it and the cold shoe on the body have a small metal peg at the rear of the shoe, which seems to prevent a flash from being mounted in the '"traditinal" way.
The "peg" was for accessories that had a hollow screw that screwed down around the peg for a secure mount. My 50mm rangefinder for my Universal mounts this way. Seems I remember it has a slot so you can remove it with a jewelers screwdriver.