You are right, I went back out and dug out that Tank. As you will see it has a bad dent in the Pass. front corner, I was trying to get out, with no luck. I also found a small leak in the process. So I am thinking of replacing that Tank, too bad!!!!
It does have Black paint, just on the bottom, and it looks to have been "brushed" on.(and after the straps were in place) I guess I had just considered it a "backyard" detail job. Sorry! I am attaching a pic.!