hi Randy. It may have been the owner's aesthetic preference for a different green. Some are not that keen on Garden Metallic Green, but I sure liked it when I had the car. I attach a picture of that 51 Frazer Manhattan when I had it and you can see that it had the original color as tagged which was how Lowell Johnson painted the car. I recall about 12 years ago seeing a 51 Manhattan HT for sale from a classic car vendor in St. Louis and that car was a Glass Green body with Crystal Green painted roof. I thought it was stunning but my wife hated it. To each his own.
With all the impressive colors offered by KF it is tempting to paint a car to one's preferences, regardless of the original tags. I was very impressed recently when I saw a 48 Kaiser Special at the Gilmore Show that was Lambs Wool (cream) over Academy Blue. It really classed up the otherwise minimalist look of a Kaiser Special. I did not have the KFOCI handbook to know if that was the original tagged color and it probably was but either way, I could see painting a 49-50 Frazer that color just for the looks of it. But then I attend shows for enjoyment, not for competition. If I had a very rare car like a 51 Frazer MH HT though, I would be more inclined to stay with the car's original color designations.
