I'd be really surprised if there were any damage, because stress on this stage was much lower than in the normal launch. Reentry burn was so long and strong that virtually all breaking during descent was due to it, there was nearly no aerodynamic breaking, so there was nearly nothing to stress the vehicle - and during ascent, MECO was with a lot of fuel still in the tank so terminal acceleration was much lower than during normal launch.
We'll see how the stage from SES-9 launch will feel like - it will be a nearly max 'reusable' payload launch so reentry burn will have to be minimal.
