Well, I'm not sure when KNIX is tracing its founding. It signed on the air in 1961 as KNIX. So the station's 50th anniversary was in 2011. But in the 1960s, it was beautiful music, as were several other stations in Phoenix, including KMEO-AM-FM 740 and 96.9. But country wasn't a format you'd put on FM in those days, since listeners had to buy a more expensive FM radio, and station owners thought country fans were not FM owners.
Buck Owens bought KNIX in 1968. So that anniversary was last year. But he switched to Country music the following year, which was 1969, so this would be KNIX's 50th anniversary as a country station. Owens already had bought KUZZ-AM-FM in Bakersfield, and that was #1 with country music there. So it was logical that he'd put country music on AM 1580, a daytimer which he also had acquired, along with 102.5 KNIX, making the two stations KNIX-AM-FM.