The solid tip of horns and antlers were once cut off and drilled for use as buttons/toggles. It’s amusing that plastic toggles were made to imitate this, when they are clearly not horn!
Here’s information about toggles that, as a land lubber, I was unaware!
Both these type of fasteners were unusual for Beutron. These two cards date post July 1970, when the name Beutron was printed in block letters rather than cursive.