Seems just lazy propaganda. There are multiple videos of ISIS forces using Humvees captured from the Iraqi army[1], so the idea that Humvees = US is silly.
[1] https://www.reddit.com/r/syriancivilwar/comments/27vlvw/comp...
[1] https://www.reddit.com/r/syriancivilwar/comments/27vlvw/comp...
No, but he Iraqi army has plenty of Badger Armored Vehicles which is based on the Cougar and visually quite similar.