There’s was also a suppressed revolver issued to OSS Agents in the ’40s. I think that was by S&W, though I’m not completely sure. Silenced revolvers do exist, but, they’re a bit of a rarity. And retrofitting a revolver requires a lot more than just threading the barrel and calling it a day.
I didn’t really want to get into it in in because the post already had enough parenthetical tangents, but, since we’re here now. The major advantages are, revolvers can use a standard double action configuration, and there aren’t many moving parts that need to be muffled, unlike an automatic. The disadvantage is, they are harder to load, and have lower ammo capacities, you know, like normal revolvers.