Yes, yes it is. It's likely one of the "tweet-tweet-tweet" whistlers in the third deck sitting under the press box (or sitting near a crowd mic) who gets excited EVERY TIME a Blackhawk touches the puck. The Wolves have had the same type of person at their games the last two years. Every time the home team gets into the neutral zone with the puck someone "tweet-tweet-tweet" whistles.
I heard the same noise on the Comcast-Sportsnet Chicago feed for the Nashville and Vancouver rounds.
Just be glad you haven't heard the crowd start "SHOOT! SHOOT!" on the Power Plays. They'll yell it if the 'Hawks are in possession deep in their own end.