Gen 2 are radial front brakes and the wheel hub is 5mm wider than a Gen1 (unless it's a Factory/Racing with Radial brakes)
Gen 1 & 2 rear wheel offset is different and you need to make up some replacement spacers to swap between them.
£34 and you can fit gen 1 front wheel to gen 2 bikes.
The rear wheel is very slightly different too. There is loads on AF1 about it, but the bottom line is gen 1 wheel is about 3mm narrower on the chain side than the gen 2 wheel. You can either make up a spacer (which i did) or simply fit as is. There are no clearance issues with 180 rear tyre........with a 190 the chain can be a bit close to the tyre edge without the spacer.