Seattle averaged 172.6 and Dallas was at 147.1.
150 is doable providing you believe all the hype about Abdullah and Bell supposedly will be ready come game 1. Heck, I would settle for 130 in reality. It's really about keeping defenses guessing which will generate more 1st downs and all the other stuff that comes with it, like scoring consistently and not for only one half of each game.
You said from Backs. Seattle got over 800 from Wilson. Stafford isn't getting 800. Seattle was closer to 115 out of RBs