Just try to find the nicest one possible. Generally the metal is in pretty good condition, it is just the stock that tends to be beat up (obviously there are exemptions). All the I have owned about 5 K31s, most of them being built in the 50s just because those tend to be the nicest ones I can find. Some get all rapped up about the type of stock (Walnut or Beech), but that is personal preference, I just go for the stock in the best condition.