I found myself in New York City on a Wednesday morning and was able to monitor the FBI Control interoperability check-in on 167.7875 MHz, P-25. FBI Control checked in with various stations as they have in the past:
http://mt-fedfiles.blogspot.com/2007/06/nyc-fbi-interop-check-in.html
However, this time I was able to confirm the use of 407.7750 MHz, 88.5pl as part of this Interop Net.
The activity on the UHF repeater was all analog, while the traffic on the VHF side
was all P-25.
Shortly after the check-in net was finished, traffic on the VHF repeater went to encrypted.