Well, a competent engineer would really have to weigh in to provide details on stresses and loads, metal fatigue details and all kinds of other things. You can be that they did this at the factory at the time. They might well have built into the unibody enough added strength. But without knowing that, I would not want to risk it. I liken it to going to tearing out a wall before knowing if it is a load bearing wall or not. House might stay up for a decade, and then suddenly just fail.
