The anniversary wasn't as expected but it was a rather large increase to some area attractions. Paid visitation at Jamestown Settlement was up 53% over 2006
http://historyisfun.org/JYF-ATTENDANCE-SURPASSES-ONE-MILLION.htm. Also included in said article is the quote, “Inclusion of our message in collective local and state promotional efforts that reached a national audience was key,” Bak said. “The Foundation worked closely with area partners, including Colonial Williamsburg, Busch Gardens Europe and Historic Jamestowne, to encourage a longer length of stay by providing a number of cooperative ticket options to visit multiple attractions. Cooperative ticket sales accounted for about 20 percent of individual paid admissions.”
This article bemoans the attendance on Jamestown's 2007 culminating event, the May Anniversary Weekend while averring that overall attendance at Jamestown National Park was up 153% over the prior year as of the end of July
http://fredericksburg.com/News/FLS/2007/092007/09072007/314802. No actual attendance numbers are provided and I can not find any.
Colonial Williamsburg only showed an uptick of 5% in their paid attendance
http://www.history.org/Foundation/Annualrpt07/index.cfm. As an apologia, the article says that true attendance at CW is difficult to tabulate due to being able to access the area/restaurants/shops without a ticket. They also state that night programs haven't been counted in admissions but will be henceforth. Additionally, with a multiple day ticket or annual pass CW can't seem to accurately account for attendance due to lack of a 'gate.'
I think, that while the anniversary wasn't as greatly attended as expected it seems clear that a large increase in tourism in the Williamsburg area happened that year. Griffon's advent and advertising surely helped the large surge in Busch's attendance but was probably also due to a concerted advertising effort by the local attractions.