22 long started fading into the sunset not long after 1900, and
was pretty much a dead cartridge by WWII. There were not to the
best of my knowledge ANY firearms in the US chambered ONLY for
22 Long or 22 Short and Long (no Long Rifle) after WWII.
Sturm Ruger didn't make ANYTHING until 1949.
I suppose it's possible that Ruger made pistols for some obscure
export market that didn't allow 22 LR, but if they did they didn't
If the pistol has no markings--why do you think it's a Ruger??????