It depends on what color green you now have on your car. One of the original colors offered by Ford for the 1929 Tudor was "Vagabon Green" on the bottom major portion of the body. See my avatar photo of my car painted that same color. I believe it is PPG 122 acrylic lacquer. The upper back and belt moulding are "Rock Moss Green" and the window reveals are "Buff" color. The pin striping is "Straw" color....as per the Judging Standards. Most Model A parts suppliers sell the book, Model A Paint Guide which has paint chips showing the various colors offered for different years and models.
You can bring to down to your local jobber and they can scan the color giving you a greater chance of a match for a paint that has a few years on it (fade, etc).