I have a hard time searching and remembering who recommended what. Lots of great advice. Here's the pic of the driver side. You're right. Dangerous place and easy to get damaged. I also noticed the exhaust wasn't attached at the rear. So many loose ends.
It suspiciously like a fuel pressure regulator. Those don't belong at the rear end. Put it up on the passenger fenderwell or cowl where it can be easily adjusted. You want to regulate the pressure at the carb not at the back bumper.