When Ensign Tyson (Russ Tamblyn)first proclaims he's an ensign, he is clearly wearing silver bars, the insignia of a lieutenant, junior grade. An ensign wears gold bars--known familiarly as "chocolate bars."
During the sequence where they're building the recreation hall, one of the guys taking part in the construction is seen wearing a Milwaukee Braves baseball cap. The Braves didn't move from Boston to Milwaukee until 1953.
Lt. Ross Pendleton: [describing the running of the grunion]
During this time of the year the slippery little creatures come up on the beach, stop, spawn, then go out to sea again.