Ignore my advice and you'll never see your meteorite again. That's really no skin off my back, but I think most people would rather have a neat "maybe-a-meteorite" sitting on their own desk instead of having it sit on the desk of the researcher they sent it to. When these guys open your package to find what they immediately recognize to be a meteorite worth hundreds if not thousands of dollars, I can guarantee you they won't be annoyed at the inconvenience and they sure as shit won't think twice about the return postage you send with it. They'll add it to their collection.