What firearms were available for the Anti-ISIL Militias during the war against ISIL in Iraq?

So, i had a friend who went and joined an Anti-ISIL militia in Iraq in 2016, and he fought with them for a year before getting injured and going home.

He was first issued a battered up AKM, but ended up with a G3. Would western guns like that be actually common among those groups? which ones would be common(ish)?

how would those guns make it to Iraq?