calling for collector's to assist with the restoration being performed by the conservators at the Emil Buehler Conservation Laboratory by providing reference material from their collections to restore the ship to it August 1967 appearance for the filming of the "The Trouble with Tribbles" when the model was tweaked the last time while the show was in production.
The next alteration to the ship model apparently occurred after 1976 so the goal is reference material from around 1967 to before 1976 where they can get a good solid look at the ship and how it looked it its final show configuration. As a result they are not asking for screenshots from the show or material that a google search could provide but those unique photos and other one of a kind reference material that collector's might have discovered over the years that few would even be aware exist. It might even be an old picture when the model was put on display at Huntington Beach in 1972 for Space Week. The idea is the more pictures they can find, the more details that can lead to an accurate as possible restoration. If you think you might have such useful material, the Smithsonian is asking you to reach out to them via email at StarshipEnterprise@si.edu. They are not asking collector's to donate those items but simply make them available as references during the restoration which they hope to complete in time for the shows 50th Anniversary when the model goes on display at the Steven F. Udvar-Hazy Center's Milestones of Flight Hall in 2016.