.  According to the Airliners.net description of the CRJ-100 and 200, "The original CRJ-100 series - the 100, 100ER and 100LR - was augmented by the 200 series (with more efficient engines) in 1995."  This particular aircraft was manufactured six years after the switchover.  The confusion is because this flight was usually operated by a CRJ-100, but since seating is the same they can often be substituted for one another