Staredown

I always thought that they overdid it with the Enterprises battle damage in Star Trek III because in Star Trek II Khan only damaged the Enterprise in her Portside (Left)

In the scene when shes was backing away from the doomed Reliant in the Mutara Nebula her starboard side was untouched. 

But then I remember back in late 1983 when they were filming Star Trek III there was a fire in Paramount studios where alot of movie props and studios were either fire damaged or completely destroyed. The 6 ft. Enterprise model was one of the props that got fire damaged but still intact.

Since making a new model to replace the one that was damaged was too costly and would setback production they decided to go with the model with the extra damage on it since they were planning to have the Enterprise destroyed anyway which Nimoy wanted it to be kept a secret but the scene of her being blown apart was leaked and shown in commercial clips back in `84