Oh, it was in the US Army manual, all right, and there were S&W revolvers made in that caliber. I had one. It was a 5" barrel version with a plain wooden grip. The barrel was indeed marked with ".38 S&W Ctg." designation. The revolver was literally covered with stamps, both British and Austrian, so it had been around. There were no importer markings.
Although that particular revolver was really listed in the manual, which I promise to dig out and reference, it doesn't follow that any were actually used on active service overseas, presumably there were some somewhere. However, there was only the one in that caliber while at the same time there were about six or eight other revolver models also listed, I think all in .38 special caliber. I suspect there were still .45 ACP revolvers there, too, but I don't remember right now. There weren't any in .455 though.
There were a lot of war surplus revolvers sold in the 1950s and judging from advertisments in old gun magazines, a lot of them were modified, presumably to make them more marketable. It looked like a lot had barrels shortened to two inches (they lack the forward latch under the barrel but have a full length ejector rod), nickel plated and have new grips of stag (real or plastic, can't tell). I think there have been threads about such variations here before.
There were even some Ruger revolvers used by the military before they were done with revolvers.