Picky question on Stepside Chain Placement

[77 ChevySport]

Have a question on my 1977 Chevy Stepside. I'm sure it would apply to many more years. Here Goes>

On the bolt (square shaft) that holds the chain and is attached to the side
panel of the truck is where my question applies. On the end where there is a loupe (circle) that holds the chain: should the circle be horizontal or vertical?
I have seen it both ways at truck shows. How did the factory attach this part? The GM "Illustrated" book does not give a good picture. Also was the
chain painted black on all the stepsides? Thanks in advance--Larry