No, the voltmeter should have one terminal GROUNDED and the "hot" lead connected to "switched" ignition. On Mopars that terminal is a dedicated terminal on the ign switch, and as I said earlier, powers the ignition, regulator, etc,
but....it ALSO goes to the instrument cluster and powers the gauges through the voltage limiter
You should be able to splice into that. Bear in mind that originally, that circuit IS NOT FUSED.