I vote no missiles. Last time I fought an Order GB with 1 missile, I killed it solo with my Orchid Bomber because it relied too heavily on it's missiles. I didn't even use any CMs to kill it.
If you have any rear firing turrets it can't hurt to put a missile on it, but don't rely on it to kill your opponents. Chain firing Basics seems to be a good way to kill bombers, it's the only tactic I've had used against me that has done more than scratch my shield in a group fight.