In the US, 58% of the 2001 models came with the 2L HOT engine, 6% were the 2.3L (Viggen), and the rest were the base 2L.
It gets more complicated when you add in models sold in Europe and elsewhere, because the model names (S, SE, etc) do not come with the same equipment in other countries. In other words, as posted above, you have to look at the VIN to be sure.
edit:
List of Saab engine types, 1985-2002, pasted from the Saab EPC:
B201 2.0 l engine with single camshaft
B202 2.0 l engine with twin camshafts, -1993
B202S 2.0 l turbocharged engine with twin camshafts, without charge air cooler
B204 I 2.0 l engine with twin camshafts and twin balancer shafts
B204L/E/R 2.0 l turbocharged engine with twin camshafts and twin balancer shafts, charge air cooler, normal/low/high power output
B204S 2.0 l turbocharged engine with twin camshafts and twin balancer shafts, without charge air cooler
B205L/E/R 2.0 l turbocharged engine with twin camshafts and twin balancer shafts, charge air cooler, normal/low/high power output
B206 2.0 l engine with twin camshafts, 1994
B212 2.1 l engine with twin camshafts
B234 I 2.3 l engine with twin camshafts and twin balancer shafts
B234L/E/R 2.3 l turbocharged engine with twin camshafts and twin balancer shafts, charge air cooler, normal/low/high power output
B235E/R 2.3 l turbocharged engine with twin camshafts and twin balancer shafts, charge air cooler, normal/low/high power output
B258 2.5 l 6-cyl. engine
B308 3.0 l 6-cyl. engine
B308E 3.0 6-cyl. turbocharged engine