Model A Pickup Bed Info Needed

[Dan Partain]

While doing some research I have found a pickup bed with waffle stamped rivets in an unusual location on the bed. I haven't seen any other beds with waffled rivets in this location. These do look like they were done at the assembly plant.
If you guys with pickup beds can take a look at your beds, please let us know if you see another one like this. Old rusty beds out behind the barn qualify for inspection too.
Here are a couple of photos.
Thanks!