The part of the gauge as pictured above uses a proprietary threaded nut to seal the compression sleeve. So it is absoultely beyond any reasonable doubt not 1/8" npt. The brass fittings in above photo are the nut,ferrule and the line adapter to engine block. Larger thread is 1/8"npt, commonly used on most early mopar engines.
A short line and adapter to your braided line is one way to connect it.
A gauge with a fitting that can be adapted would be a better way to go.
Honestly,who would want a potential oil leak in the passenger compartment? Go electric.