Well, any battle damage might be considered to be recent hah, be it scratches, bullet impacts etc etc. That's why I put nu rust on mine, just dents & scratches.
I'd definitely for for some light and coherent scratches where the plates might scrub together or against the scenery. Elbow joints, knees, fingers, knuckles, some scratches on the shoulder pads and lower leg armour, some wear & tear around any small panels and plugs. Once in-theatre, Marines can be expected to stay in the field for days or weeks on end without any decent support so any use of weathering due to usage is OK hah, but neglect-weathering is a no-no.
Also, some oil or grease marks around the joints might look good.