Listed here is a 1953-54 Chevy Locking Gas Cap NOS from GM
This gas cap is new NOS and was offered by GM as an accessory starting in 1953.
For those of you who are not up to date on all parts 1949-1954 there is a difference between the gas caps used on the 1949-1952 Chevy and the cap used on the 1953 or 1954 Chevy. They are not interchangeable. The 1949-1952 Chevy gas cap has the locking ears near the center of the cap. The 1953-1954 Chevy gas caps have locking ears on the outside edge of the cap. The picture of the inside of the cap does show the locking ears.
The chrome is nice, it does have the key and the rubber seal is in good condition.