In 1949 a tool kit became a GM accessory (only a jack and lug wrench were standard). The tool kit shown at the link above is the accessory tool kit that became available in 1949. In 1949, the spark plug size changed.
The 47-48 tool kit was quite similar but it had a spark plug socket that was smaller. Prior to 1947-2nd the standard equipment tool kit included an adjustable wrench.
