My bad, I thought that Gibbs (started first 9 games as a frosh last yr) was a walk-on but actually she was a spring signee. only averaged 7.7 ppg as a HS senior but apparently for a very good team.
However, there was another walk-on (besides the two mentioned) as recently as 11-12's roster:
"THIS SEASON: Kemana Otosi enters her first season at USC as a walk-on guard."
I just remember always seeing unfamiliar names of M. Cooper's rosters and assuming they were walk-ons. For instance, on last year's roster there was a "Malia Cravens" on the roster but not in the stats at all nor on this upcoming year's roster and her bio said:
"THIS SEASON
Malia Cravens enters her first season at USC as a transfer from Hawai'i.
AT HAWAI'ICravens did not compete in her first season at Hawai'i."
...but apparently she had a scholarship?
I see a couple other spring signees/transfers that were unknown on the HS circuit who only show up on the roster one year the gone the next.