oh no, I just put the gun in there for a reference to size.. that Colt is a 2013 XSE govt.The manual has an address that includes a zip code.
Zip codes were introduced in 1963 and became mandatory for 2nd/3rd class mailers in 1967, so I'm going to guess that it dates to the early 70s.
Is the pistol original to the box? I couldn't make out the slide markings - is it a series 70?