Fuel tank sending unit ground strap

I'm pretty sure the tubing, its hangers, and frame rails were all fairly clean contact points when new. I don't imagine undercoating would get between those contacts either. 40 plus years later the contacts could be weaker. Only an ohms meter knows for sure.
I agree there is a better way to do most anything but at what cost ?
If you never stop redesigning you never get the first completed product out the door.
"It'll last 10 years, ship it." LOL