I think all but two of those trucks is medium green. One is a darker green and one might be the 511 turquoise.
I found one GMC truck that was the turqoise color I wanted at a junkyard, but the SPID was missing. I kept looking and think I found a match. The current color code is 1862, color number 53B, and is called turqoise metalic or poly. Here is the radio delete I took from it to match.