As a retired submariner with six boats under my belt, retiring in 1996, I have seen boats in the anti-fouling red and black configuration. I have seen boats that were painted all black. But, I have never seen one that was painted a dark grey on the lower hull. That is a new one for me. And, these differences did appear throughout my tenure in submarines from the late 1970's through 1996.
What does really interest me is that the masts and antennaes seem to be sporting a new color. When I retired, submarines had the familiar splotched appearance of silvery grey and black. Now, they appear to be an almost soot-black or dark grey, at least in Groton.
Bill