This was from their fifth game against California this year, and there was no stripe on the helmet. The design was based off the 1966-67 logo, the only past helmet with such a design before the Cal game this year. (The unknown 1969 helmet design, if the 100 Years logo was not a full-term design, may have a UU as well, but that design has stripes).
Utah marketed the game as a throwback, implying that there was a past year with this helmet design, but so far no such year in their chronology has proven support. More pictures from the gallery here: