Do not think that is NW metal -- it's CO Express or CO Connection with RJ145 or Dash-8 (turboprop, but actually nicer than the RJ!) aircraft.
You will get Elite benefits with your WP number in the PNR. However, it's all coach seating, so not much there to look forward to.
If you book at a lower fare class, you will only get 50% EQM!