I haven't seen Inter parking the bus against a team for a long time. They have been used to playing with 3 defenders and an offense-oriented game at the same time.
Inter Milan aren't really an attacking team, of course they have their own way of approaching games and getting goals, but they are not the kind of team that holds possession and attacks constantly, they do not have the necessary quality in their squad to do that. Having said that, there's no doubt that Inter would park the bus against City, even most of the best clubs in the world would do that, when you come up against City you have to respect them and accept the fact that they would control most aspects of the game, Inter have to do one thing, defend and wait to hurt City on the counter.
For a team like inter Milan to face a team like Manchester city and come out victorious, will require that inter milan play with great wisdom, not just about man power or strategy, and the kind of wisdom required to beat Manchester city is one I don't think inter Milan possess, but like you said, the only chance inter Milan do have against Manchester city is to focus more on defending and keeping the ball away from their goal post, while they look for open opportunities to try to score against Manchester city, though there is no guarantee of any kind in doing this, but this worth something to try.
Look forward to the game in the 10th of this month.