Hey cuzin, I was going to do that on my 59. But...the steel diamond plate was VERY expensive, and it was also REALLY heavy. I was going to use 3/16s thick to avoid bends/warps etc. It was also going to be akward to make on my 9x6 ft bed.

When you get oil on wood it just sucks it up. Oil on steel is going to stay there for quite a while.

You'll also need some drain holes.