On the top flap of the box (inside) is printed ”K77DE22TS”. Other than that, no traditional date stamp of any kind. On another forum a member said that he thought they were made early 60’s just from the style of the box.
The Mark-5 plastic shot collar appears in the 1962 catalog, with the Super-X and Xpert still in paper hulls. The plastic hulls appear in the 1964 catalog, compression formed for the Super-X (like AAs but with higher brass) and poly-formed (plastic tube with a fiber base wad) for the Xpert. Those style boxes were in use through 1972. By 1973 The Western Super-X had moved into the white boxes --
in 1971 the Xpert got replaced with the compression formed Upland --
The date is in the lot number, but deciphering is a bit complicated, because of repeating cycle of year code.
Probably way more information than you were looking for, but here's a reference
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