I guess, unofficially, the last song 100.5 played as "Jack-FM" was "Clocks" by Coldplay - according to Yes.com, it was the last song played at 11:48 PM local time on Friday night. And if you go to the KKJJ-FM player -
http://player.play.it/player/player.html?v=4.3.10&id=483 - you'll see that the song "currently" playing is "Clocks". All this while a string of songs, mostly with cold segues, and no commercials, plays on 100.5 FM. There are some liners promoting KXNT about to "get stronger" on Monday with the addition of 100.5 FM, with songs such as "Hold On, I'm Comin'" by Sam & Dave and "Home Sweet Home" by Motley Crue played in the background. Virtually no references to "Jack" at all, and I'm willing to bet that has been the case since "Clocks" played on Friday night at the aforementioned time. However, at the original time of this posting, I heard a liner referring to the old "Jack" format, though it did not include the voice of Howard Cogan. Just a caller saying, "Jack, you stole my mother." Followed by a Matchbox Twenty song - yet the player still shows Coldplay.
Now, I just heard a Cogan-voiced liner, saying, ironically: "Jack-FM, rockin' Vegas 24/7." (Well, for at least another hour and ten minutes, anyway...)