So this may be a dumb question, but can you Target Lock emplacements? The rules for Target Lock cover enemy ships, but emplacements are terrain; there is no special line in there about target locking them. It seems like you should be able to Target Lock them; after all Luke starts to use a Targeting Computer to target the thermal exhaust port on the Deathstar! Is there something I'm missing, or am I reading too much into the Target Lock rules?
We allowed target locks on emplacements in our game. Didn't break anything. I would assume without rules otherwise we did the right thing.