In the opening, Navy Ensigns are wearing both surface officer and submarine officer warfare devices. It would make sense for a LTJG or higher to do so but not ensigns. Regardless, officers with both are rare, and no submariner would ever wear his dolphins lower than a SWO button.
Ensigns in the Navy (the lowest Commissioned rank) are typically people with less than 3 years of service and do not wear Navy Achievement, Navy Commendation and Meritorious Service and Air Medals.
In the opening, the Naval officers are wearing dress white uniforms, but one of them has black socks on.