Hi KC! It's good to hear from you again!
This object is just shell and whistle. . . no rattle. I have seen the older vintage rattles (and absolutely love them), but not one quite like this. As I mentioned the old rumor in the family is that it was a bosan's whistle or a slave whistle.
Any idea of how old? I know my grandmother (and I am 52) had it and gave it to my father. However, she only knew the rumors of its use.
Again, good to "hear" from you!