bed mount question - bent frame from towing?

[Chuck78]

After owning my truck for a short while, I noticed when the previous owner replaced the bed wood with some oak plywood on my 62 GMC panel, they left a out the bed mount bolts on all but the rear mounts. The ones over the gas tank were completely missing, as evidenced by the empty space left behind. Then, moving forward to directly over the axle, I alarmingly noticed that the side to side cross brace under the bed wood was sitting directly on the frame. I didn't think this was supposed to be like that, and also shortly after, when hauling tools and having a 6 foot level laying in the back, I noticed that the bed wood seemed to hump up in this location a slight bit. I then started wondering if the previous owner's had bent the rear of the frame down from towing, as it does have a heavy duty rec. hitch. Can anyone confirm this frame/bed support contact for me, or tell me that it's gonna be alright?
I need to go pull out the rubber bed mat and re-examine the problem wth the 6 foot level directly on the wood...

When I first got the truck, I looked at the frame rails and thought to myself, wow, those aren't very tall for using a receiver hitch to tow a car trailer! I had thought at that point that I should reinforce the frame with some heavy duty C-channel. Now I am wondering if I need to unbolt the bed mounts and jack the whole truck up directly in front of the back bumper mounts to the frame, and try and use something to bend the rear frame rails back upwards if this is the case. It is the stronger X-frame, but the frame channel height on this whole generation of trucks left me wondering about their towing capabilities due to the minimal frame rear of the back axle. If it had leafs rather than coils, I would think it would have been less of a problem, but the coils don't support the frame back that far.

Might be time to get out the welder! I can get pictures soon if needed.

Thanks guys.