Dave,
Your 1998 Contessa does not have a rubber roof. It has a fiberglass roof that may have had a rubberized coating like a pick-up bed liner applied to it by someone in the past. The bed liner type coatings usually do not require any special care or maintenance.
A rubber roof is a special rubber membrane that is stretched over the plywood roof on most travel trailers, fifth wheels, gas motorhomes, and entry level diesel pushers. A rubber roof does need extra care and replacement around every 10 or 15 years, depending on usage.
Gerald