The history cards are a great discovery. I just spent a day in the Special Collections department of the Kennedy Library going through all of KCPR's records trying to reconstruct the origins of the station, and here is the actual timeline all spelled out!
On March 8, 1968, the California State Polytechnic College filed an application for a construction permit to build a non-commercial educational FM station on 91.3MHz. But although they included the required 3 copies of FCC Form 340, they only filed one copy of the exhibits. The FCC requested two more copies of the exhibits before it would process the application. Additional copies of the exhibits were submitted in April to complete the application. Then on June 5, 1968, the FCC sent President Kennedy a telegram explaining that Program Test Authority would only be granted after the construction permit was granted, construction completed and a license application was filed. A week later, on June 13, the construction permit was granted.
KCPR scheduled their first broadcast on July 29, 1968, which was a little early since they since they hadn't filed the license application yet. The broadcast was planned to start at 6pm but, due to technical problems, they didn't get on the air until 7:05pm. Then they only stayed on for two hours but that was long enough for President Kennedy to say a few words and for the station to play a documentary of his life called "The Life of Robert". Continued technical problems led to them signing off at 9pm.
Afterwards, they realized that KCPR didn't have Program Test Authority so they prepared and filed the license application on August 8, 1968. The the history cards tell us that PTA was granted on Sept 20, 1968. KCPR began regularly scheduled programing on September 30, 1968 and thus the empire was forged.