With the "G" prefix to your serial number, you do not have a pre-64 model 70. I believe you are refering to the pre-64 model 70 when you say "more sought after." A pre-64 model 70 has controlled round feeding, which means there is a claw extractor on the side of the bolt. The claw positively grips the cartridge head for feeding and extracting. This is a Mauser action. The push feed bolt does not have this claw. With that low of a "G" prefix serial number, I doubt your rifle has the claw extractor. Winchester did later revert to the claw extractor in their classic series, but it was probably sometime after you bought your rifle. Pre-64s were considered to have better fit and finish, post 64s to have somewhat cheaper parts. Winchester was assailed for this, but they had to do something as the model 70 cost more than Remington rifles and Winchester was losing sales. There is nothing wrong with push feed. If your rifle is a good shooter, you have a nice rifle. Can't give you an exact date of manufacture, but again, with that low of a "G" prefix serial number, I'd say mid to late 60s.
