I think the only difference, of any significance, id the little patches of gray ribbon that are sewn on the left sleeve cuff and left trouser pocket flap. This denotes the uniform is FR and not standard ACU.
Note that there were many small changes to the ACU over the years. I even got a pair of trousers that were pulled from inventory and updated to have the crotch seam reinforced. Nice secondary label in there saying who did the work and when. So be careful when comparing any of the ACUs together because you might think there's some sort of difference between FR and regular, for example, but it's just comparing newer FR to older ACU.