Status for reservations made prior to earning Gold status

I have a bunch of reservations made before I qualified for Gold status. So when I turn up at these hotels, will they know of my Gold status (making me eligible for benefits such as free breakfast) or will I have a battle of sorts to claim these?

Since I am on the road now, even if a new HH card with my Gold status gets mailed to my home, I will not get it before I reach these hotels.