Correct. You may even purchase them at the gate; I've seen the Hawaii flights from OAK, SAN and PDX frequently offer upgrades for $150 each way and you can purchase them if available irrespective of whether you're traveling on a paid fare or an award.
Originally Posted by
ken98230
While there are no free upgrades for MVP and above on award tickets, my understanding that if there is paid upgrades available you may purchase one. The option will show up when you do online check in.