electrical wires

It wasn't totally unheard of for the factory to add on at that side of the ALT' gauge. That's how they powered the clock addition in a rallye dash.
If they look like OEM terminals, wires taped into harness and all, they probably are.
The line in / red wire side of the gauge should be marked on the circuit board. That one stands alone. All the blacks will go on the other unmarked side.