You can always ask for an upgrade if you wish, at any property, with status or no...
... but don't expect much based on your Gold status.
You should expect:
* Complimentary late checkout
* 50% bonus on Starpoints earned on eligible spend
* No charge for your newspaper
But Gold doesn't get you much in the way of upgrades. Sometimes Golds will get upgraded (as will some folks who aren't SPG members at all) but the only thing you're entitled to is a 'preferred room' (subject to availability). What this really means is that the hotel should try not to stick you in the worst room at hte property....