Yvonne Strahovski wears a pair of Anon Informant sunglasses with a gold frame and gradient lenses in the television series Chuck. The Anon sunglasses can clearly be seen in Season 1, Episode 11, 'Chuck Versus the Crown Vic'. Click on the photos to see a larger version. The little engraved Anon logos on the side of the arms (in the gold part) are clearly visible.

These Anon Informant sunglasses come in different color combinations and have a suggested retail price of $125 but are available online for less than $50, for example at Amazon.com or Ski Informant.

Thanks to Michael, who identified this pair.

Reference: Anon sunglasses, Gold frame, brown gradient lenses