The Cal .30 LR cartridge FAT65E5 was designated in March 1953. But, in July it was re-designated the FAT233 so there are probably no cartridges or boxes with the original designation. (This information from Col. Frank Hackley)
The T233 was loaded with the T28 bullet, a 150 grain, boattailed, 10 ogive, GMCS, lead core. It would later become the M80.
The label on this box was very badly faded so I printed a copy, enhanced it as best I could, and then re-photographed it. Cartridges in the box are headstamped FA 52. Take special note of the load. 47.4 grains of W846-2 for a velocity of 2832 f/s at 78 feet. A hot load! I have no idea who or when the pressure figure was edited.
So, you will encounter at least three Ball cartridges headstamped FA 52. The FAT65E4, FAT233, and FAT104E1.It will take careful magnet work and maybe even pulling the bullets to tell one from the other. (And keep a sharp eye open for a possible FAT65E3)