CBP Customs in Canada

I just returned from a quick trip to Montreal and passed through the US Customs Pre-Clearance at Toronto's Pearson Airport (YYZ). I spotted a CBP Customs officer at the end of the Pre-Clearance area with a VHF Astro Saber radio. While waiting for my departing flight to the US, I listened to see if I could fingure out what they might be using there, but had no success.

I have been told that CBP Customs officers at Vancouver (YVR) use the CBP Customs NET 1 frequency (165.2375 MHz), but I have never caught them while in Canada. Anyone confirmed any usage of VHF channels by CBP at YYZ?