The differences between the 1gen and 2nd gen front wheel attachment I believe are the use of a different axle for the 2nd gen and the loss of the two right side spacers. So, to use a 1gen front wheel on a 2nd gen, you would need to use the wheel plus the 1gen axle and the two spacers on the right side. To use a 2nd gen wheel on a 1gen, you would use the wheel with the 2nd gen axle and leave out the two 1gen spacers. The 2nd gen axle has the inner fork spacer included and the wheel hub is wider so an extra spacer against the wheel is not needed. I think I have this correct. You would need the 2nd gen wheel and the 2nd gen axle to make this work. I think.
I don't know if the brake rotors are different, ie, the rotor carrier is flatter on the 2nd gen.
Edit: I just read that the rotors are not interchangeable, so I don't know if the wheel swap would work without swapping the rotors as well. Tovar would know for sure, PM him.