As Gold, Hampton Inn Vancouver (very nice property), upgraded me to a full suite with full kitchen and separate bedroom, without even asking.

It doesn't hurt to ask, but be prepared for "No", and occasionally, an attitude along with it. You might also want to do a search here for the particular property you are staying in. Some (like Vancouver), have several threads showing a pattern of nice upgrades, and others, a pattern of "no", with an attitude.