My guild was a GDKP guild for P1 in SOD. Plus, I know of several other groups that were GDKP in p1. Plus my experience in Classic and all the communities I was apart of back then. Odd how someone within the community would know a lot about said community. So I can assure you.
And I think more people than you believe are 40 at this point. Maybe they haven’t yet raided or will be raiding soon. But we are at over two weeks and on our third weekend of the content. Even just questing alone would have helped you attain 40 by now with just a couple hours a day. I spend a lot of my time in front of the AH and still leveled.