According the the 1965 Rotunda and FoMoCo accessories catalog floor mats for the Mustang came in; black, white, red, blue and palamino.The other Ford cars had some other colors like turquoise, clear, gold and burgundy. (The gold was in the Ford line and they look nothing like the mustang mat)I would say based on this book that no, green was not avaible in early 65. Maby 66? I don't have that catalog. Also the catalog does not show the two diffrent mustang mat styles and only lists one part number. I can not tell from the crappy photo if there is a pony on these or not in the catalog.
The price a whopping $7.95 for the front and $4.95 for the rear.