Well, I can only help a little. This is an Amber piece of Corning in the Visions line. According to my Corning book, Corning first sales tested their Visions line in 1981 through Imoco, Inc a Company based in Irving TX, and through a company called LeClair out of Clinton, NJ. It says that if you get a piece of very strange looking Visions, it likely came from one of these 2 companies. The actual Visions cookware line would not mature until 1983.
So I would say this is one of the early "test" pieces that Corning did for the line. I'm not sure what it would be used for though. It almost appears to be an underplate of some sort to me. No pieces like this are shown in my book. I wish I could be of more help.