This vintage piece is unmarked, and closely resembles the old Waltco SAF-T-SHEATH knives, but it has some noticeable differences. This could be a fish knife, and I seem to remember that some Waltco-looking knives of this sort were made in Finland. Therefore it is possible that this is an old Finnish balisong, perhaps intended for use as a camping/fishing knife. I"ve included some pictures of the old Waltco, which is USA made, for reference.