Hiyah Bobby! Good to see you here.
First off, I'm not marriedMrs. Wong was my grandmother.
Secondly, from the images that are on the ad, they aren't the best, which is why I asked to see some better pics of the sides and a full image of the animal.
From what I could see, it doesn't appear to be IMO.
Typical YBs have blushing up the sides, a mottled side pattern along the bellies, and don't have "yellow bellies".
THIS is a Yellowbelly...
And it is a subtle morph to be difficult to distinguish in some cases, or else we wouldn't be having this debate.
The Hunters Guide to morphs may help you a bit more in being able to pick out Yellowbellies..