I am not familiar with step sides.
Is the problem in the fact that the one side that is not available and does or does not have a gas tank door?
Just an idea.......
Can the door be filled, or if it needs a door take a fender that is junk EXCEPT for the door, take the door out with some surrounding metal and graft the door flipped over onto the blank fender??
Or is this just too insane??
Just curious??... and thinking on the keyboard.......you can just tell me to go away if you want...........
Also I try to refer people that are looking for stuff to try
www.car-part.com
You can be supprised at what you can find there....
Just my .02

CCDually