I'm putting a (used) replacement bed on my 2001 Ford F-150XLT. The salavage yard that I purchased the replacement bed from delivered it upside down. Explaining that if the bed is set upright, the lower panels are not strong enough to support the weight and may crumple under.
I'm nearly to the point that I'm ready to do the actual bed swap. In process of removing old bed from truck. So it time to turn the bed over upright. Where it may need to remain so for a few hours, perhaps a day.
Is it true that the panels will not support the weight, or was that an excuse to get me to let them unload it as it was loaded on their truck without the effort of turning it over? Your speedy advice VERY much appreciated!

Yes, the bottom of the exterior sides are not strong enough to support the bed....you can set the bed on a stand so to speak where it rest on or near the same locations as the frame comes in contact