I think it is not Metropolitan Government itself, but the office (役所).
Wouldn’t the actual office building be 都庁舎? From 庁舎?
Technically 都庁 does refer to the office itself, thats how 都庁見学 exist!
Obviously its not a terrible mistake, but I do believe it is a mistake nonetheless.
Isn’t this like saying “the White House will announce a decision later today.” No one thinks the building is going to speak.
It’s synonymous with the government that uses the building.
Fun fact, on the line I commute every day there is a station called 都庁前 which is (Im assuming) in front of the Tokyo Metropolitan Office
Right, but I feel like it should have the office part added seeing as it is common to refer to the office itself that way.
EDIT: In case that wasn’t clear, I mean added as a synonym. Not added to the currently existing “metropolitan government” and having it as the only definition.