Found my dads original 1971 duster!

This looks OK.
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What was touching?

As far as the ammeter goes. Take it off and check the studs are tight and then test for resistance. It shouldn't have any measureable resistance. Compare to touching the meters probes together. That's about it for the meter. There's no electronics . Its just mechanical.

The fuel gage is a bit more complicated because of its dual function but for a guy who can do as much as you do I think you can tackle it too (if you want).
Here’s a pic of it off. Studs are tight. You can see the burn mark here better. Just about to test it for resistance. Have to google how to. lol. Just found my multi meter

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