The Comedian is knocking over one of those Marxist republics in South America after 1977 in his poster:
He's wearing the 'gimp' mask which he only adopted some eight years after the JFK assassination...
Check out Blake's seedy hotel room: bamboo and twine bed/chair, broken blinds at the windows, ceiling fan to cool the air, ashtray bearing the word 'DOS', Roman Catholic crucifix on the wall, plus the shuttered windows and curved rooftop tiles of the buildings opposite - all so not Dallas circa 1963...
The people opposite are of Latino appearance; the falling streamers and stray balloons suggest a fiesta-like celebration is in progress...
The sunglasses, moustache and military uniform sporting gentlemen depicted in the poster-within-a-poster (nice 'meta' foreshadowing, as WATCHMEN went on to feature a comic-within-a-comic) is the very epitome of a stereotypical South American 'El Presidente'-type dictator, who is no doubt the focus for the celebrations taking place outside Blake's window and also appears in The Comedian's rifle cross hairs at that precise moment; the poster lettering obscured by Blake's window surround is very likely to read VIVA in full...
The Nite Owl II poster quote is
almost identical to a line of speech from Dan which appears in actual print at VII.8.5... but the date on that poster is certainly incorrect. Even assuming that Dan went on to repeat the same line he first spoke in 1985, as depicted in the comic panel referred to, by the following year 1986 Dan Dreiberg had to all intents and purposes disappeared, to be replaced by the Sam Hollis identity.
Remember, these posters were in the can and distributed to comics stores before the general release of WATCHMEN #1: Moore, Gibbons and Higgins were still incredibly busy finishing the actual twelve issue series proper at the time, so the occasional inconsistency and lack of colouration in these promotional items can be forgiven!
The best you'll get to professionally coloured versions are the ones reproduced reasonably faithfully in 2008 to publicise the WATCHMEN movie.And use of the spelling 'coloured' in the thread title suggests that the OP wouldn't naturally refer to a certain ethnicity as being "African-American": here in Blighty, the terms Black African, Black Afro-Caribbean or simply Black are the norm. But it was still a witty Ziller Zinger - nice one!