And prior to KLEF it was KARO from 1960 to 1964, although I'm not sure it was on the air continuously for that whole time. The owners were absentee I think.
Did KARO ever exist on the air? I've seen it listed in old White's Radio Logs from the early 60's, but a gotcha with WRL was that it would often list stations that were still in the construction permit stage and not yet on the air. Many such facilities never actually made it on the air, or were born under different call signs.
I recall other sources such as 100000watts.com listing the 94.5 license going back to November 1964 (KLEF>KJYY>KLDE>KTBZ) so either KARO never made it on the air, or was a completely different license that went out of business, opening up the frequency to a different applicant that would become KLEF.
Anyone know for sure? The history of FM often becomes rather murky once you go back more than 40 years.