Propane Tanks: Gas Valves Question?

Butch.. interesting point which brings back a recollection of my first encounter with this rig before the purchase. This guy was definately not a DIY specialist. I have found so many things that were done in a more than puzzling, indeed a stupid way. For instance, one tail light on the TC had electrical tape on it that was a good distance overlapping onto the hot bulb. I thought that was odd so pulled it appart and found that the pot metal sheathing the bulb locks into was a bit out of shape. I got a good laugh out of that one & it began to show a picture of a D/A who should not be allowed near any tools. I grew up working in the garage with my Dad and became a Contractor with so many tools I am burried in them... Of course, I simply took out my best needle nose and grabbed it securely with a grip all the way back to the rear of the socket and nudged it in a bit.. Problem solved.. But I digress!
When this individual showed me the LP bay, there was one horiz and one vert tank in there. He had a big hook on the side of the camper to pull the vert tank out and hang it there when drawing from that tank. Since I'm still very new to RVing, I had a very strong inkling that an LP tank hanging over the side sounded a bit wonky but just listened and watched.