The Tax Stamp on the box is that of the United States Playing Card Company (USPCC). Which indicates USPCC being the deck's manufacturer, and this type of Tax Stamp was used from 1940 - 1965.

Additionally, USPCC did date code their decks with an alpha character on the Ace of Spades. In this instance, the letter "T". The letter "T" was used to indicate decks made in 1914, 1934, 1954, 1974, 1994 and 2014. It is not known what the numbers represent, and in this instance, it is a coincidence that it appears to be a year (1957).

So, the overlap date of the Tax Stamp and the letter "T" is 1954.

Jim