I found out that the "G" stands for General Shaver Co. which is a division of Remington Rand. Most Colt branded Magazines That I have seen have a "C made by Checkmate.
I have a Stainless 8rd Colt marked magazine, I think it is from the early 1970's, Thats when Colt had thier magazine vendors start stamping the "Prancing pony", It two tone Stainless, The Base up to about 1/8" darker then the Body of the Magazine, It is "G" marked.
Any information will be...