I haven't gotten on my UT122 quite yet... but 6-12" away from that, so hopefully this weekend.
From a design perspective, they are for sure going to be muchmore similar than different. Built around same construction, same flex pattern and stiffness profile, and similar rocker profile. Both are going to be absolute lightsabers in untracked wild snow.
Where I think the difference will stand out... the 132 just has more taper, so a level up in breakable crust and windskin, but a little more neutral stance too. The 122 has less taper in comparison (but far more than most skis), so a little more able to pressure the tip and a touch more support fore-aft in comparision. And of course, being narrower is a little easier when on an established skin track, where the 132 is (IMO) an absolute dream breaking trail.
Not sure if helpful, but my honest 0.02