I seriously doubt that Marriott would exercise ROFR on a gold week at Manor Club at almost any price. Marriott's gold season in Williamsburg is very short and not very desirable. Most of the weeks that logically should be gold at that resort were included in the extra-long platinum season. In my opinion, half of the platinum season should really be gold. The gold season should be silver, and the silver season should really be bronze. (Based on weather, seasonal activities, etc.)
Compare the seasons at the Marriotts in South Carolina with the seasons in Williamsburg. I think the seasons at Hilton Head and Myrtle Beach are much more realistic. Indeed, I think that the extra-long platinum season is one of the reasons that platinum weeks at Manor Club are relatively cheap on the re-sale market. There's just too many of them. That, in turn, also depresses the prices for the gold season weeks which aren't nearly as attractive as gold weeks at Myrtle Beach or HHI.
Bottom Line: I wouldn't buy a gold week at Manor Club. But if you are going to, I don't think you will need to worry about ROFR.
Steve