I can name two upgraded highway-to-freeway routes in So CA: the I-215 from Riverside/Moreno Valley to Murrieta/Temecula was upgraded to total freeway status, and the 86 from Indio/Coachella which is still in construction should go all the way to El Centro (I-8) or Calexico (the Mexican border with Mexicali).
The only segment of 86 that is a freeway is the former Route 86S south of I-10 (and only for a bit) - the partial freeway/expressway routing bypassing Brawley is Route 78 and Route 111, with 86 through El Centro a candidate for decommissioning.
At the risk of going off topic to this thread, I believe that SR 86 from Brawley southward will eventually be decommissioned, with the preferred north-south route through Coachella Valley, Salton Sea, and Imperial Valley following SR 86, SR 78, SR 111, and a split between SR 111 to Calexico or I-8 to SR 7 to the Calexico II Border Crossing. This would likely imply that SR 86 would go no further south than its northern intersection with SR 78 ... or someone will attempt to "rationalize" the expressway-freeway route under one route number, which may mean a major realignment of SR 86 or SR 111 (or an extension of SR 7 or SR 115, or an entirely new route designation to unify the preferred corridor). I am also wondering about SR 111 northwest of Indio and whether any of it will be left as it is gradually decommissioned in phases to the local cities between Indio and Palm Springs.
Okay, now back to the High Desert Corridor and waiting for environmental study results...