Could be. The nine big Los Angeles FM signal footprints, in order from the largest, are KPFK, KBIG/KLOS (tie), KRTH, KTWV, KRRL, KCBS, KLVE, and KKGO. But of those, only KRRL has lackluster ratings, ranging 1.6 to 2.0 over the past half year. KPFK of course doesn't count.
I wonder how much of the audience 97.1 built for KNX will follow it back to 1070. If a significant portion does, this could make for an interesting strategy for prolonging the lives of AM properties. Take an FM you are already going to flip, "pop up store" flip it to your lagging AM news station for a while, and then send the newly built audience to AM upon flipping the FM to what you had planned all along.