a really nice GM high note horn with part number stamp 291. could be from a 1963 Impala, 1969 ?truck, 1966 Pontiac, or a bunch of other cars my dad and I have ?parted out the last 60 ?years. lot's more to come!! if anybody knows what the 291 or any other numbers came out of, please drop me a line. there's no swelling between the rivets. ? ?