Pseudo-spoilery post disclaimer:
Yeah, same dude, shared universe. Not really a spoiler, but Arrow pops up for a brief moment in the pilot. If you saw the 5 minute trailer for the Flash show, then you pretty much have seen the pilot. The trailer is all from this episode.
If I were to guess I'd say it was never intended to air, based on how quickly it establishes basically everything from the Flash universe. They left out a good deal of character development in order to get him suited up and fighting someone quickly, which is fine in order to get the powers that be to pick up the show.
I'm stoked for it though. I love how they're getting directly into meta-human stuff. Couple really neat (and kind of surprising in one case) references to Flash characters throughout. And that newspaper clipping at the end dropped a pretty big bomb.