Mine has that bracket, welded to the bottom of the u-shaped part of the pulpit - but it snapped off at the weld, when the prev owner had it. Eventually I'll see if someone can weld it back, on the hard.
I don't want to penetrate the hull, so I'm leaving it where it is. For the half-season in 2010 I used it, I made a hardwood wedge that keeps the lamp assembly vertical, given that the center pulpit stanchion is at an angle. I screwed the fitting to this, and used plastic wire ties to fix the wedge to the stanchion. I used a piece of rubber sheet (from Home Depot) to create friction between the wedge and stanchion so it wouldn't rotate or slide. Of course, the rubber has disintegrated from UV. I will likely try to make a slot in the wood and use a stainless hose clamp for the upcoming season.
Not the best position, but at least if it gets banged it can be fixed - so far, the lamp assembly itself has not been damaged.