A 59/66 is 15 parts, since it has a muzzle attachment; you would have to replace 5 parts or more; the
stock is 1 part, the upper handguard is 1 part (usually if you replace the stock, you replace the
handguard as well), the magazine body is 1 part, and the magazine follower is 1 part.
You are still 1 listed part short.