johnny,
Typically you will need to post pictures to get help identifying a disc. Then you may get more answers than you want. The stamp is helpful info, even more helpful if it is a unique stamp. A tounament stamp will unfortuantely not qualify as unique unless it is a major event that someone here played in the specific year you have.
From your description I doubt someone will be able to identify the disc. Are the chains all the way around or just around a certain part? More importantly, if it is Innova, what is written on the underside? If you can't see anything written, a weight number and hopefully some letters, you may be able to hold it in the light to see the indentation where the ink has faded away. Innova has a section on their web page with all their codes for what a disc is, new and old. I trust someone else who reads this will post a link.
