The originals were injection molded and they did not have 3D plastic printing in those days. I think a printed one will be strong enough if printed in the right kind of plastic. I think the best plastic to use will be black nylon - if I recall correctly that is UV stabilized. Guessing on that - I'm not a plastics guru and there are a zillion different types of plastic - some better, some worse.
I will draw it up in Solidworks - it's a 3D CAD program. Typically places that do 3D printing use .step files and I can save the design in that format. I would like to find a place on CSC where I can upload these files along with a text file for recommendations on plastics to use etc. That way anyone could just download the file and print whatever small part they need. I also have the file for the female side of the ladder clip that I did a while back for Jonbrush. Unfortunately I can't remember what kind of plastic we used for that but it was a harder plastic than nylon. Here is a .jpg of that:
