They are horizontal recessed plastic rod holders in the gunnels of my 1984 V 20. The plastic is actually on the inside of the glass supported by some wood strips it must be a bandaid fix from a previous owner. It seems that I have seen the same set up in a few other boats but their rod holders look loke they are one piece with a flange that can be screwed into the glass like the outside of a replacement hatch.

Man, thanks for answering this. This site is the coolest thing. If you know of any company that makes these kind of things please let me know.