Most likely fake.
The one in the video looks like the current, longstanding and only version they make.
I would refer to coldsteel.com rather than an auction site known for fakes.
The link you provided above lists approximately 4 Gladius swords, from the top of the page, which are not Cold Steel. They are knock offs...I have found something new on this. Yesterday popped up a new version at my searchlist on ebay and it looks like a real one.
Search for: " COLD STEEL GLADIUS SWORD 61CMS "
or directly: https://www.ebay.com/sch/i.html?_fr...=2&_sop=10&_odkw=cold+steel+gladius&_osacat=0
The seller looks ok for me but it´s only listed from Australia. If this is realy original it´s extremly identical to the United Cutlery Gladius.