Mike,
You're right about Barry Weeks--one of the finest human beings around!
From my experience, I think it will be difficult (or near impossible?) to secure a small sample of the actual paint. Paint vendors are generally not willing to mix up a simple sample--you may have to purchase a quart. We used to have a vendor in our area who was willing to mix up a pint, but they are no longer in business. Last time I was looking at various colors, I had to order a couple quarts from Autocolor Library (and this gets pretty expensive!).
At any rate, Autocolor Library sells both quarts and gallons of Brewster Green, in both acrylic enamel single stage and urethane basecoat/clearcoat. Jim Carter Trucks sells the color in enamel single stage, but I think only in gallons. If you have a good local autopaint vendor, I would check if they'd be willing to mix up a pint.
Good luck!
Jim