One of the first things I take a picture of when I have a box apart is the mold date stamp. It's usually on the inside of the case back and shows the date when the part was injection molded. While not a definitive created-on-date, it's as close as we can get to when a box was manufactured.
The oldest date stamp I have is from a Victor RC-550: February 22, 1978.

What date stamps are in your boxes?
Go!
=ml=
The oldest date stamp I have is from a Victor RC-550: February 22, 1978.

What date stamps are in your boxes?

Go!
=ml=