Dave,
I have a 49 3100 and I must say I like your idea of removing the chains and going with something much cleaner.
How do you keep the bar which is inside the tailgate from vibrating out when your going down the road? I am interested to see how it would work on a 48-53 tailgate because the tailgate mounts inside the frame of the box and it appears your bars would get in the way of it closing.
Kudos to you for taking an idea and making it come alive. I like this idea, not having to drill/cut/grind on a perfectly good tailgate.
Good luck!
Adam