No, I have not monitored Post Falls (I am in southern Idaho), but I certainly would try to monitor and see what you get. Program it as an APCO25 site with only one frequency; use the ID Search mode and see what happens. I have a 996T, not a 396T. I have never tried what I am suggesting on a conventional system, but I have been monitoring the IIMARS trunked systems in Bannock and Bingham Counties for several months now.
This appears to be only a temporary license, but I am sure it will work into the 700 Mhz IIMARS when Kootenai County implements their part of the overall system. I believe, currently, Bannock County is fully operational and Bingham and Ada Counties are in operational/test modes on their parts of the IIMARS. I don't know what the implementation schedule for Kootenai County is.