Wasn't the pistol Sledge had and old .45 breakdown half moon clip revolver from WWI that had been sent to him by his father?
Yes, his father sent it to him after he arrived in the South Pacific

Wasn't the pistol Sledge had and old .45 breakdown half moon clip revolver from WWI that had been sent to him by his father?
Iran is not a terrorist country!LittleZeke aka: "LittleBrain" 3/10/15

From what I've read, the rules regarding sidearms or looted weapons from the enemy were not as strict during WW2 as they were in future wars. As mentioned by another person, it probably depended on how your commanding officer felt about it, but I've heard stories of veterans coming back from the war with bags full of pistols. I always used to think that the front line infantry was issued the standard 1911, but apparently this wasn't always the case.
"Oh yeah, one more thing.where can I get a pizza?."

As I understand it, the assumption was that enlisted men would be shooting with their rifles, while the officers, directing the troops from behind, just carried a sidearm for protection if a charging Japanese soldier got through the lines?

Thanks for your response. However, in this instance the pistol Sledge carried was not a captured weapon.

I believe that captured enemy weapons were considered contraband. But it depended on your NCO or officer as to whether he was a stickler for enforcing the regulation.