Does anyone know what the bracket that bolts to the bed wood near the gas door is for?

When I refinished my bed wood I forgot to drill one of the holes and I hate to do it now. Esp if I don't even know what it's for.

Thanks

 

I brought this up years ago and there were no answers on it. I did not put it back in....

 

I thought maybe it was some kind of anode but I'm not sure it's the right kind of material. Well at least now I know I'm not the only one in the dark! Lol