I was LMO when the IAT was made official, so maybe I can help here. The belt is a cool find that I don't recall being brought to my attention at the time. That said, one of the things we must keep in mind when dealing with comic book references is that a costume can look drastically different from issue to issue or even from cover art to the inside of the pages. Sometimes this is due to varying artists, and sometimes from frame to frame things are remarkably different even from the same artist. What we have to look at is what the character looks like most of the time across all the references. With the IAT, I can tell you there were quite a few references from a number of sources, and it was quite a challenge to find the consistent visual story to standardize. I think overall the finished result is pretty good, despite a few stumbling blocks along the way.
It's kind of like this: in ANH there are stormtroopers. There are two CRLs for these, stunt and hero. Both are seen throughout the film in a wide array of frames and scenes. Now, there are other variations seen on screen including duct tape on the Tantive as well as the famous Mr. No Stripes. Neither is in the CRL. Instead we have to go with what we see most of the time with consistency.
I hope this perspective helps.