Hi Rob,
Generally speaking, the only time subs have any numbers or markings painted on them other than draft markings is during sea trials. When in service, many boats use detachable numbers with magnets on the back to secure them to the sail in port only. They are removed and stored below when the boat gets underway. Markings around the deck hatches are only present during seatrials. They are used to guide a DSRV into place if the boat sinks. They are removed and stored below when the boat gets underway.
As built the hull above the waterline is generally black and below is hull red. Sometimes the sonar dome appears to be a different
shade of black. Once in service, the boats are repainted topside(above the waterline) on an as needed basis. This can result in a patch work of different shades depending on where the boat operates (hot or cold) and how it is applied. Subs are drydocked about every 4 or 5 years. At that time the hull below the waterline is inspected and painted much like the topside (sometimes the whole thing is done, sometimes only the worst areas. Sometimes it i
s black and sometimes it is hull red. I recommend finding a pictures of a boat you like and using it. It really does vary over time.
Hope this answers your questions,
Rob

Does the Seawolf Class have Anechoic Tiles or sound-abating rubber coating on the hull?If I remember correctly, it made the hull look duller or flat even painted.

Interesting picture. I wonder who the Admiral was onboard at the time. Whom ever it was they are a 3 star, so he must have been important.