My only concern with the dealer making it right, is making it worse… I would ask what it is they intend to do to remediate.

I agree that is is highly unlikely that you would have lost the bolts in the wash.

I would have light concerns with them removing door panels or headliner to locate any water damage. Just make sure they put it back together without any broken clips or wonky panels.

Personally I would ask for an comped extended warranty to combat against any long term electrical issues.

I would also want this event documented in writing in case you ever have water related issues which may might not fall under a factory warranty.