why do the battle packs say 7.62x45 that cartridge was not invented until 1940s

On the front of the battlepack cases it is labeled 7.62X45 this cartridge wasnt invented until the 1940s and wasnt formally introduced until 1952. totally a small knitpicky thing but some of use are gun nerds. Could it be a typo from 7.62x54R or 7.62x63 which is more commonly known as 30-06 which didnt see a ton of action other possibility would be 7.7X56R (303 birttsh)