Ammeter Bypass a Must?

Yeah, that's why it's so important to inspect every now and again IF you're gonna use the original "stuff". Like on mine, it had some green corrosion "funk" all around both studs. It was working, but sporadic. Once I got everything operating room clean, it started working good again. I have removed the cluster a couple of times since just to "look" and make sure everything is still good. Only four screws, after all......versus a burnt down car.
I must be missing something, as it appeared to me, that I can't get into the gauge unit to tighten the studs? On my 66 satellite I started every one of those pens for that round connector for the instrument cluster this applied to power and did the little fivev solid-state upgrade.. back when one Radio Shack in town at least old something even though the people that work there get go how to do anything but cell phones but I managed to find what I needed