It's easy to understand Rockne model confusion. Though I suspect the logic of their designations is long lost to history.
The two prototypes produced by Ralph Vail and Roy Cole were never called Rocknes. In fact, I don't believe anyone knows if they were ever called anything. They were produced by Vail and Cole under contract to Willys-Overland. And when W-O determined not to produce them, the two engineers got to keep the prototypes.
One day as Vail was out driving his, he decided to stop in South Bend and show it to Albert Erskine, who drove it and agreed to make it a Studebaker product that same day.
To name the new product a Rockne, in homage to Knute Rockne, was an afterthought, as Knute was killed on March 31, 1931; and the first Rocknes did not roll off the assembly line for another nine months.
The 1932 Rockne of Vail-Cole design was marketed as the Model '65'; but in the Studebaker Parts depot it was a Model 30.
The 1933 Rockne of Vail-Cole design was marketed as the Model '10'; but in the Studebaker Parts depot it was a Model 31.
To further confuse matters, Barney Roos was assigned the task of outfitting the Studebaker Model '54' to be a larger model Rockne, and designated the Model '75'; which is identified in the Parts Depot as a Model 41.
I'm sure that clears things up. 🥴
So, those parts would NOT be from a 1931 Rockne. But they COULD be Model 31 parts, in which case they would be from a 1933 Model '10'.