This barometer seems to be missing the needle that indicates the change in atmosphere pressure. (Needle shown can be adjusted to indicate current pressure, so you can compare.) As I understand it, there should be two needles. This device does not easily come apart, microscopic screws and washers, etc. The unit is in such nice cosmetic shape, I'm struggling to wonder how an internal needle like that could have gone missing? I do not see remnants of a broken needle. No clues on the base, right? Getting ready to sell "As Is" for parts, wanted to be sure there wasn't some obvious explanation. All thoughts much appreciated.