I don't know about where you're located, but in North East Oklahoma, "490" is widely used but numerous agencies in our area. I like to call it the "CB Ch. 19" of the public safety world. That holds true for this area because it's usually some hillbillies that want to talk on it. Most little agencies that use it for a primary frequency all use separate PL tones so they don't interfere with one another.
I monitor .490 all the time, every now and then I'll hear some interagency police traffic on it.... SS is right though, it's hardly ever anything worth hearing I do hear Porter FD quite often being paged by Wagoner CO.
Alot of dispatch centers still have access to one or both frequencies, not that they monitor them. I even noticed the other day that Tulsa PD has .670 tucked away on a mutual aide tab on their consoles!
I quit scanning 490 on my radio a while back so I wasn't for sure on Perkins. Recently I've heard Coyle mainly on the Logan Co. SO frequency mainly. Everyone is right though in that most agencies I've seen still have it in their radios just in case. Interoperability=490 is about right!