From personal experience, I would say that dogs can be just as picky as cats. Diamond used to like her (for treats only) canned dog food cold. Now she'll only eat it room temperature. She also liked a spoon of the canned mixed in with her dry (add a little water and you got wonderful gravy!), not any more. Dry or nothing. She also has a preference over the flavor of the food. She perfers the Whitefish and Potatoe to the Lamb and Rice.
So I'd say...Yup...dogs can be just as fussy.