very late cretaceous to eocene

Yes, the Ozark Mountains are older than the Rocky Mountains. The Ozarks formed around 300 million years ago during the Alleghenian orogeny, while the Rocky Mountains started forming around 50 million years ago during the Laramide orogeny.

About 75 millions years ago, the Grand Canyon area was a plateau (the Colorado Plateau) that was uplifted an estimated 2 miles (3.2 km) during the Laramide Orogeny.

The Rockies formed first, around 80 million years ago during the Laramide orogeny. The Alps formed later, about 30-40 million years ago, due to the collision of the African and Eurasian tectonic plates.

Jason A. Lillegraven has written:

'A new look at the Laramide orogeny in the Seminoe and Shirley mountains, Freezeout Hills, and Hanna Basin, south-central Wyoming' -- subject(s): Geology, Structural, Guidebooks, Orogeny, Structural Geology

'Latest Cretaceous mammals of upper part of Edmonton formation of Alberta, Canada and review of marsupial-placental dichotomy in mammalian evolution' -- subject(s): Fossil Mammals, Mammals, Fossil, Paleontology