OK, so these are surely not 'butterfly knives' !!
and after pretty much pondering these half the night......I realize these are EAGLE heads!!
Use of the eagle head on military hilts pretty much goes to many nations but primarily US, and Holland with other exceptions.
These seem like other ranks type swords for sappers etc. but these typically had saw backs. The raised ridge bevel type blades look like a 19th c. type Ive seen on Civil War period 'bowie' cutlass type weapons but that is not of course a determining factor.
Still lookin'. !