It's a 1957 Ruger Standard, also known as the Mark I.
The stocks are genuine plastic, Franzite brand. I'd never heard of the brand, but they fit well and feel good. With a spare magazine that came in that original box.
Check the price on the box!
I get the impression that the previous owner was the original owner and he bought the magazine with the gun. Brand new in 1957 a Ruger Standard was $37.50. Wow.
It's a fine shooter and was utterly clogged with gunk and still functioned. Cleaned up now!
A .22 pistol is on my list of "guns everyone should own one of". I made that list decades ago when I first started shooting and I only just now got around to buying one.
Other items on that list.
Scoped bolt action centerfire rifle.
Semi-auto rifle with a detachable magazine in a military caliber.
Service sized pistol.
That's the minimum. I note that I still don't have a scoped bolt-gun. I keep getting distracted.