Well that may satisfy you but I think some will wonder just what that was. If it was a hole in the crank case you would have had oil on the floor and none in the bike.
Your dealers response is unhelpful to say the least.
But you seem to be happy at the result and finding a bolt fitting into it! but don't you mean a plug? as in,--- drain plug.
I think this will keep me awake tonight.
Again as 4444 said --can you post a picy?