Jim refers to the "state of Hawaii." However, by the time this episode aired in February 1960 Hawaii was a U.S. state. Hawaii became a state on August 21, 1959.
Toward the end of the program, Jim and Margaret are in the kitchen. Margaret is nervously telling Jim what she thought Jim's "big surprise" would be. As she is speaking, she is wiping down the kitchen counter with a dishrag when she accidentally knocks over one the four plastic canisters. It is clearly evident that the canister is 100% empty. (Normally, in the 1950s, the canisters would hold Sugar, Flour, Coffee and Tea.) When Margaret knocks over the canister, she quickly rights it, but has a pained look on her face.