You can ask Hank but I think they only hold you to the grindstone on this if its newer than 25 years old. Older than that I think its exempt from some of the more strict emission criteria.
Cut the filter open first, and see how it looks. You might be able to start with just pulling the pan and doing a visual as you slowly rotate the engine by hand and see if you can detect anything hitting. Just start with the easy stuff before diving in to a complete teardown.
