With all due respect, Sir, those are clearly M-1 Garands.
You’re right, I was looking at the bolt area and not the muzzle, so those are definitely parade rifles.
Beat me to it... The M-1 is most certainly not an M-14, even though they are related.
I am more concerned with those 8th and I Marines sloppy carriage of the rifles: There isn't a parallel line among those muzzles and the Color Guard in the photo looks like he has his rifle wrapped around his neck. I would not have put up with that level of drill proficiency when I was still in and the Gunny would have had some extra practice for those Marines.