Most of the Marines from Halo: CE are present in all of the other FPS Halo games, such as Sgt. Avery Johnson, Sgt. Pete Stacker, and Pvt. Chips Dubbo. These three Marines fought alongside the Master Chief on Installation 04, and were present at the Battle of New Mombasa (Halo 2), the Battle of Voi (Halo 3), and the Battle of Installation 00 (Halo 3). Thus, most of the Marines in the Halo games are the same throughout the series, although some new soldiers have been added, like Sgt. Banks in Halo 2.
If you mean appearance wise, it is plausable that the UNSC issued different armor and fatigues to the Marines before or during the Battle of Installation 04 (Halo: CE). It is possible that the Marines had been utilizing the Halo 2 or Halo 3-era armor and fatigues for many years, or even since the outbreak of the Human-Covenant War, but the Pillar of Autumn's crew did not adopt this newer combat gear in favor of keeping their older, tried-and-trusted armor. This hypothesis is reinforced by the fact that the PoA did not have any of the UNSC's newer weapons in their arsenal, being restricted to the aging MA5B assault rifles and M6D pistols, while the rest of the Marines utilized the state-of-the-art BR-55 battle rifles and M6C pistols as their standard-issue weapons in Halo 2. The Marines aboard the PoA may have decided to stick with the gear that they were familiar with, rather than taking the time to becomed accustomed with the new and different combat gear.