Tool kits were standard equipment through 1948. From 1949 upwards, the tool kit was an accessory.

Different sized trucks had different sized jacks.
http://chevy.oldcarmanualproject.com/chevyresto/48103.htm

The tool kits before 1947 had an adjustable wrench.

The spark plug wrench in the tool kit matched the spark plugs (which changed from 10mm to 14mm in 1949).