My site has been selling M4g discs since 4/10. They are only marked with the weight and M4 in either plastic, no G mark! It is obviously different plastic by the feel. Technically, they are 400g plastic and everything else officially out is 400 series. Proto or First Run stamp has no effect on series. By the way, PA1 and PA4 putters are being shipped out today to those that preordered!
for ABC Discs, NutSac Bags, Prodigy Disc, and Team Disc Jock apparel.