People have made their own. It is possible the center was rusted out on the one in your picture, and someone replaced the center sheet of steel.

The reproduction fiberglass tailgates come with or without the lettering. They also sell the Aluminum letters to make yours look embossed.
https://www.ebay.com/itm/F-O-R-D-Eco...p2047675.l2557

 

There was also a NOS Ford tailgate on ebay earlier this week for something like $2800.

 

Thanks guys. I'm liking my flat tailgate a lot more now. $2800.00 is a lot of money. Understand these things are like hens teeth to find.!