I have searched and found two other 571xxx 300 Win Mags with the standard Trademark instead of the circled R. I see the circled R trademark on 575xxx and later guns. Rules book is good but not perfect. The 06 stamping is baffling with 6 grooves as they specify 4 grooves for the 30-06. You just can't walk into a gunshop and find a pre 64 model 70 in 300 Win Mag to compare. They are few and far between.
