It would also depend on if it was a bigger piece or a smaller piece. The bigger pieces have cut-out inserts that are in the shape of the item to cradle it securely. This way may be okay, as long as they ship it Priority Mail with insurance. The post office seems to treat those better and they don’t have them too long to break them.
The smaller pieces are wrapped in a plastic bag, then paper inside the box. I wouldn’t trust those to go through the mail, although Watergazer sent me a PYO wolf that way, and it arrived safely. So you never know.