All of Longview's old sirens (mostly Thunderbolts along with two P-50s) were replaced with 2001-130s within the last few years. I remember seeing some of their old Thunderbolts and possibly one P-50 in a lot up for auction maybe a year or two ago, including one Thunderbolt that I distinctly remember being a 480V unit with the huge chopper transformer in the RCM1. I don't think the page for that auction lot is up any longer though, but I honestly haven't looked for it again.
The old Thunderbolts were all on a steel pole with a concrete pad at the base that the blower sat on, and I believe the wiring for the head was run inside the pole. The city had new two-way FC assemblies with the battery box and all installed on all of the old sirens quite a few years ago to not only make them compatible with the newer two-way Federal activation setup, but to make future replacement easier down the road. Now all of the prior Thunderbolt sites have a 2001-130 installed in place of the old T-bolt head, along with the RCM and blower removed. For a while there were even some sites that still had the RCM and blower in place with the 2001 up top, and they even appeared to still be hooked up to the new controls, but they're long gone now.
Here's an older map I made on Google Maps for those interested in seeing their sirens. I'm sure if you go back to prior street view imagery, you'll see at least some of the Thunderbolts and the P-50s. I'm pretty sure you should also be able to see at least one of those sites with the 2001 on the pole and a blower/RCM still hanging out.