Persistence - If you have the old cover, take it to a plastics company and have a new one made. I think I paid about $100.00 for the last one I had made.
Tiara changed their gel-coat color in 2000/2001(I believe this was when the color change occurred) from a creamy eggshell to fresh white. Keep this in mind when buying fiberglass parts. You can always paint or gel-coat to match, but you should be aware of the color difference. The 1998 should be the older creamy color and if installing on a newer boat, there will be a clear color difference unless you re-gel it or paint it to match.
I'm able to closely match the older gel-coat by adding just the smallest amount of brown tint and an even smaller amount of yellow to a large amount of white by trial and error. It always passes the 10 ft. rule and still looks great up close. Capt. George