Sending unit ground strap on stainless

Yes and no. The gasket does isolate the back side of the sender from the tank but the lock ring contacts both the tank and sending unit on the front.
On mine I drilled a 1/4" hole on the corner of the tank. The aftermarket tanks usually have a flange with plenty of material OUTSIDE of the weld. From there I did a braided ground strap to the frame. The original grounding strap does not work well with sending units that have larger output line.
Absolutely agree "it should" but I would ask. Then why did the engineers find the need to fabricate the grounding device attached on each side of the rubber hose @ the metal fuel line. Contact should be complete some where in the mix with the tank straps to the body more efficiently than the flange ring. Heck just through the flow of fuel in the line should make a complete circuit. But then I just pulled a 16hr run again and no sleep maybe I'm missing something. I can learn.