Fuel gauge wiring question

I was leery opening the fuel gauge and doing the mod. No need to be. It was easy. Just plan on where you mount the ivr.
IVr has just been ordered.
Question, the RTE instructions state to mount it to one of the circuit boards grounding points, but up in post #5 by CFD244, it looks like it is just attached to the plastic body of the panel, would this make any kind of a difference?