I just posted this on the Toolboxes thread...
Snap-on made the Par-X economy line from the mid 1960's to the mid 1980's. I'm not sure the boxes were date coded, but if they were, they would look like the annual single digit Snap-on date codes in that timespan. Besides their limited run (20 years), the offerings were limited as well (something on the order of 60+ tools, max), and many trucks would not carry them. Consequently, the tools are uncommonly found in the wild, and the top boxes (2-, 3-, and 4-drawer models) are even rarer than the tools. I have to say, I have never seen a pin-striped box and I suspect that is a PO's aftermarket handiwork.
I know the following members have or had a Par-X box at one time. They may be able to help. Send them a PM.
elidas
Lookin4'67Galaxieconv
caltemus