Hello,
This site: http://www.motorhomemagazine.com/category/rv-how-to/dinghy-towing-guide/
produces a towing guide for all makes and models each year. You can go to the website and download past guides for every year auto back to 2002, I think.
Stan
I looked at these pictures and see that it was titled in Illinois, not Indiana. That might be helpful information. That style of Illinois plate was from the mid-90's, I think.
Stan