It will work. Many have done it. Supposedly it's not *ideal* as the swing arm length change that came with Gen II made things a bit different.
That is only half of the “not ideal” problem with transferring a GEN1 Wilber’s to a GEN2/3 swing arm. Wilber’s shocks come with very light springs and a excessive amount of preload to compensate for the light spring. My Wilber’s came with a 646 lb spring when a 800 spring is what I really needed. Adding the 800 lb spring was pretty easy but the shock should have been revalved to compensate for the heavier spring and the ride quality suffered unless I added another 50 lbs of weight. As such, the 800 spring was still much too light for riding 2-up.
Yamaha got its act together with the GEN3 shocks, both in terms of spring size and damping. If you put your Wilber’s on the ‘13, keep the old shock until you are sure the Wilber’s is an improvement. In my case it was not, I kept my 08 with Wilber’s for several months after I bought the ‘13, rode them back to back under different conditions multiple times, and eventually sold the 08 with the Wilber’s.