I think I would go with a whole new roof. Winnebago has an issue in that the edge of the roof's must be kept sealed to make sure the stays sealed. If part of it came off in a storm it is possible some more could come off either in another storm or more likely going down the highway. With the age of the motor home and if the rest of it is in good shape and if you plan to keep it for some time, I think I would go for an entire new roof. Then do the 6 month inspections to make sure the rood edges are sealed or re-dealed. It is a tough call, Good luck either way you go.
Howard & Connie. USAF Retired
2007 Newmar KSDP tow Jeep 4dr wrangler
member of IRV2since 2003