The Spartan on the left and the one furthest into the background seem to have identical armor... maybe twins? Just saying. It's a possibility, anyway, seeing how many Spartan IV's 343 said are canonically on the Infinity.
Also looks like 343 gave the Marines US Army-style body armor on the chest.
I wonder how amazed they'll be when they discover the chief? like because as far as they all know all SPARTAN II's are dead or M.I.A so they'll probably be in shock that Johnny is still kicking even after missing for 4 yours in space outside the milkyway. I can't wait to play!