Sorry, amigo, I never did get an answer - Ruger revolvers were never military issue that I know of, but we had four. No holsters, no speedloaders, not a single round of ammo - I had to buy my own AND get Gunner's permission to shoot it. It shot left, badly.
But no, not one person could tell me why we had for Ruger revolvers in a US warships' armory. When the ship was decommissioned in 1994, I assume they went to the base armory, and probably disposed of from there who knows where, maybe gifted to Admirals and such.