It does appear to be green, but I'm looking at a scan, and so I cannot be sure.
Of course, blue cancels often appear green with time, or on buff covers.
Then there are the not so true-greens, which are somewhere in between green and blue.
Its always good to find a reference / comparison copy, so keep looking.
There are a lot of "Salisbury's", around. I did a quick scan of the American Stampless Cover Catalog, and these listings showed up for the New York version .... not sure if its yours or not.
Quote:
SALISBURY/N.Y.( 1 84 1 -50's;30 ; PAID/3[arc]; Red, Black) . .
Same(Green) . . . . . . . . . . . . . . . . . . .
Same( 1 847;27,NOR; Red , Black) . . . . . . . . . . . . . . . . . .
SALISBURY/N . Y. ( 1 850's; stencil C-28; PA I D/3; Blue, Green)
SALISBURY/N . Y. ( 1 853; 28;5; Blue) . .