There is no designation between a wagon or sedan on the timing belt codes, you would need the VIN plate to ID that but they have the same motors basically. It looks like your on the right track, heres the list ive found that has most of the engine IDs in it for the codes and does indeed have this listed as....
JDM A.1 MY01 7 1-Aug-00 31-Mar-01 Sedan WRX NB (at)
JDM A.1 MY01 7 1-Aug-00 31-Mar-01 Sport Wagon 20K (at)
this file also has some more details as far as specs go, hope it helps.
http://share.subiefiles.com/share/te...Code_Model.xls