The words are correct, but the word-order you've used seems a bit strange to me -- not wrong, but not quite like natural speech, either.
Russian word-order is very flexible, and yet some word-orders are encountered much more often than others. Personally, I think that in this case it's best to have "оказалась" in the middle -- either "Волком оказалась собака" or "Собака оказалась волком." (There's possibly a slight difference in nuance, because in general, putting a word at the very end of a sentence can tend to emphasize it.)
To me, the order "Оказалась волком собака" sounds like it should be a question, with a "?" at the end and a strong emphasis on the second "-а-" in the verb ("оказАлась волком собака?"), meaning "Did the dog in fact turn out to be a wolf?"