The Cougar is not a really collectible bow, to most anyway, so you will not hurt or increase the value by refinishing it. It is a semi-recurve, therefore a bit less desirable than a fully recurve bow. They are great shooters though and should give you years of good service. The creme color you describe is probably a hardrock maple riser. Kind of plain jane, but a good riser material. I am not sure how far back the Cougar goes, but I know it was made as early as 1960, and probably earlier. It was a low cost entry bow at the time. It was my first composite bow, and at the time I was plenty proud of it. I eventually gave it to a guy that was wanting to get into archery. Wish I had kept it now for my collection.
The glass color will not help on determining the year. The lower target weights were all white glass, and I have seen hunting weights all reddish brown. I don't recall ever seeing one with brown back and white belly, but I guess they made some that way.