It does appear to be parkerizing. Here is an article I found on the colors.
"Other Ml rifles manufactured during this era which have seen service, have been observed to be of gloss black or dark green finish. It is believed that the gloss black is primarily a result of repeated cleaning with solvent and oil-soaked rags which gave an almost polished effect to the finish. The frequently encountered, dark green Parkerized finish is believed to be primarily a result of the compounds present in the Parkerized finish chemically reacting to the Cosmoline used for corrosion prevention during long term storage. Observations of original Garands manufactured by Springfield and Winchester indicate a change in the finish color from black to a translucent gray during the late summer of 1944. The Parkerizing process used to finish Ml's of post World War 11 manufacture appears to have returned to the charcoal black finish. If the rifle has been stored in Cosmoline, a green tint may be noted.
So, what color Parkerizing is original? Most "as new" Garands are charcoal black. Original finishes of gloss black, black with a noticeable green tint, dark olive green, a light, almost translucent gray, and translucent gray with a green cast have been observed. The variables mentioned above and more than fifty years of use and storage make it impossible to give a specific answer. However, one thing is certain; the argument among collectors and aficionados will continue."
M1s were being done at the same time frame as this Enfield. Only way to get close will be to re-Parkerize it.
Thanks for your help.
Steve