Most definitely looks purebred to me.
I'm always amazed at people who seem to think Arabians are not calm, I owned them all my life, since the early 1970's, I never had a more quiet horse than my Arabians. You will find that the Arabians that are not calm were either shown at halter (AKA the freakshow here in the U.S.), or were mistreated and mishandled, they don't put up with rough treatment.
Wanted to add, regarding being gaited. Technically, no, Arabians are not gaited. But *Raseyn, a very well-known stallion who sired many well-know horses, was known to be five-gaited, naturally. My mare had several crossed to *Raseyn. I'm not aware of any other Arabians that have done this though. http://www.geocities.ws/kiowacole2/Raseyn.html