Well, you certainly can't claim for anything that happened before the current policy started: Remember, you're asked every year whether you've had any accidents regardless of fault, and that certainly includes having a bathtab dropped on the car. Hopefully you've not renewed your policy since May '17 either, else the same rule applies.
The body shop will pretty much do whatever you ask them: Paint is paint, and metallic black isn't any more than metallic silver really so they'll just say it was painted, bill the insurer and that's that. And sure, they'll fit the spoiler too but you'll def be paying extra to them directly for that.
When my Focus was damaged back in 2001 when someone drove into the back of me, I had the wing mirror I'd knocked myself re-painted at the same time. No extra charge apart from a bit of extra labour, insurer didn't care and bodyshop got a bit of extra beer money.