As Mikeski pointed out, probably the most definitive way to tell a "2001" are the "spray pockets" on the rear 3 or so feet on the bottom edges of the hull and the "V" shaped hull shape at the transom. If it has those two things then it will undeniably be a 2001.....That is unless you look at just about any Nautique made after that. They carried that design throughout their hulls up until a few years ago and to a lesser extend still do today.
I've shared the below pic many times but in case you've never seen it....'83 on the right, '03 on the left. If you look just above the license plate on the '83 you will see the spray reliefs, and just above the rudder is the "V".
(Message edited by bmh2208 on August 24, 2009)