I'm looking at getting an extra set of rims and tires for my 2003 but gen 1 rims are scarce and I don't want steelies. If I can just change out the rotors and drums for the 5 bolt gen 2 versions then I can get some gen 2 rims and tires. There are also more choices in a 15 inch tire like the new Nokian ultra LRR eNTYRE I just may have answered my own question: I think the hubs have the lugs built in so no. Oh well.
I haven't looked, but I assume the wheels are held on with a different number of bolts on Gen 1 versus Gen 2? The bolts go through the wheel hub; the rotors and drums are held on only by being sandwiched between the hub and the wheel. You'd need to get 5-bolt hubs, and I don't think the Gen 2 hubs are compatible.