That's already been debunked. According to another member here, if you play multiplayer campaign, you can clearly see the damage on the other player's armor right out of the cryo bed.
When Cortana upgraded John's suit via nanobots, the damaged areas must have transferred over. This would also explain the more minor damage marks (scratches, dings, etc.). But I think we're all digging too deep at this point.
Useless nano bots, so lazy they never get the job done right