I'm not sure the quality of the Russian SKSs is really that much better than the those made by other countries (I have a Russian, couple Yugos, a Romanian and an Albanian), but, for me, owning one is like spitting in Stalin's eye.
Look for an all-matching rifle with good fit and finish. I'm partial to the laminated stocks that are usually replacements on refurbed rifles.
On a Russian, the gas tube and gas piston will be marked along with trigger group, bolt, bolt carrier, dust cover and receiver.
Some 1950 Russians also have the spring-loaded firing pin that was discontinued in later years. Chances of finding a 1949 are slim, but good luck to you...
Most importantly, check the bore with a light. If the shop won't let you, or it's impossible to tell its true condition due to built-up crud and they won't run a patch, then pass. There are plenty of "factory new" refurbs out there that have great bores.