Spending too much time on YouTube, I discovered this video of the reenactors of the 49th regiment. Note the color, the 'sea green' or teal of the regimental flag.
I am still amazed I got it correct. Was it that in the back of my mind remembered a reference and thus just grabbed for the right paint container or just got crazy lucky and, on a whim, used the correct paint shade?! We shall never know ;-)