HansGruber
Ronin
That’s normal for an antique.Looks to me like it may possibly be military. The stamping shows it was patented on Jan 24, 1965. Then I would guess the next two dates are issue dates and the last three are when it was reissued. I’m not military, but can’t think of any other reason for this to have that many dates and reference to it being “reissued”. Just a guess on my part.
Check for any other markings.