I finally found a WPS-2900V! I found this one near the railway in Bertram County, specifically in the town of Bodin, where I've been staying for a few days. The system ran the Air Horn and Wail signals for this test, and I did not expect the audio to be custom-made. I thought the siren was a dual-tone ESC-864 when it did four air horn blasts, but when it broke into the wail signal I knew that this was a customized system. The system doesn't even wind down, it just fades out. This siren is also completely decked out with Visu-Alert lights. Another one can be heard in the distance.
Now with an intro! Music is "Vessel" by Biddle3 (For the FNF mod called "Phantom Attack")