The 37FLH does not come with a bumper. The OP is talking about the fact that Sabre 5'ers now come with the sewer hose storage tubes from the factory. The only two places it would be mounted on the RV would be either underneath the frame just before the tires, or right after them. If you don't see one there, it may have not been installed, but is in the front storage bins. If you still can't find it, it was likely omitted from the factory build, possibly due to a major part shortage.
The one they showed in pictures I've seen was not a very long and would be way too small for me. I installed on my 37FLH one from Valterra that's adjustable in length. I installed it to the max width so I can store up to two, long sewer hoses in it and works much better, if you ask me. They're not expensive and can be had from Amazon at the link below. They're also very easy to install.
https://www.amazon.com/Valterra-Adju...s%2C218&sr=8-1