"Is that the same KMEL that was around in 1980? Doesn't seem that way. Wasn't it a rock station at one time competing with 98.5 KOME and 92.3 KSJO?"
Yes, but that was in the 70s...maybe somebody else can provide the chronology. When RKO sold the original KFRC FM (then 106.1) in the early 70s, it became "Camel 106" with the KMEL call letters, and had a rock format that competed primarily with KSAN ("Jive 95"...94.9), and to some extent the two South Bay stations - KOME and KSJO. Alex Bennett first got big in the Bay Area on Camel.
I don't remember what year they flipped to "All Hit" KMEL (they killed the "Camel"). It was Top 40, but Urban oriented, similar to 610/KFRC at the time, and probably most responsible for putting the last nails into the coffin of the Big 610. I believe Marvelous Mark McKay defected over from KFRC. By that time, Alex Bennett had left for "The Quake" at 98.9, which had a similar rock format. And yes - Howard Hoffman had a funny afternoon drive show. I believe Ric Chase came in after Hoffman left.
After that, the station didn't "flip" to a Hip Hop format, it more or less morphed into Hip Hop as the genre got bigger and bigger.