You can never really know.
Im gonna say no for 4 reasons.
1. Kelly is really clumsy, Im not surprised he goes down in any circumstance
2. oubre hits him pretty high up. Its not unreasonable for him to hit the floor. its not like he got hit in the midsection and just decided let his legs fold like a lot of guys do.
3. He gets right back up. Guys who really flop, usually make a show of it. Olynyk was p---ed and immediately went back and Oubre.
4. If you really slow the video down, Olynyk's left leg appears to get stepped on by the ref, and he attempts to stick his right leg back to stay up. Hes not able to plan the foot and he goes down.
Obviously its possible he flopped, but Oubre IS 6'7" 200+ pounds and charging from ~10 feet away.
Even if Olynyk sold the whole thing, I think an ejection was the right call and a suspension within reason.