Anything is possible, but why leave it to chance.

The first thing I'd do is go to marriott.com and look to see if when booking an award stay if they offer any points and/or cash upgrades. If they do then there's the answer to your question, along with the associated points/cash it will cost you for a particular room. If no upgrade award options are listed then I'd call the hotel directly and make the inquiry.

You mention cash upgrade at check-in, but I'd find out if they're available and book one before I travel if it's something I really wanted. A hotel can't offer you at check-in what it no longer has.

As for how Marriott treats golds and platinum on award stays...a search of the forum will reveal all kinds of answers, but personally I've always been treated very well on award stays and can not think of one instance when I wasn't upgraded to a nicer room or suite.