All ArmA games always had these darkened-texture ones models that should be changed for detailed one models. But what I noticed is that there aren't any - even darkened-texture over static weaponry as mortars.
What I suggest is to make detailed ones - like not smoldered but dirty piece of trashed mortars/HMG/artillery in pieces. Final effect should be like Iron Front scrap metal but with signs of explosion and - of course - not physically interacting one (but if it's possible then why not?).
BTW thrashing static defense/weaponry with MTBs would be woow but might be out of scope for this game.