Well, I tuned into 840 with two separate radios and my loop, and heard a jumble of KSWB, KKNX, CFCW, and probably KMAX. I recorded the last ten minutes before the hour struck. If KXNT was in there, I couldn't hear it, but I recorded it anyway.
First time I heard them was in 2012, on my Realistic TRF, early one morning during sunrise skip. After that I'd hear them periodically, depending on MW DX conditions.
Now the only Las Vegas station I can pick up -- poorly -- is KMZQ 670, in a very tight KBOI null. I've heard one of their sports AMers once. And the ranchero on 870 -- once. Harder to hear Las Vegas now on the AM band in the West.