Which Brake Booster?
That one would work, but not the one I saw several times. It was <$140 (a bit more w/ shipping to Europe!). It also appeared to be a single diaphragm type since more pancake w/ larger diameter. There used to be a Mopar one that was an obvious GM booster (round threaded rod) w/ a Mopar adapter & lever, but that was ~$170. The latest one has a flat output rod and looks more purpose-built for Mopar, but perhaps not exactly factory-correct. It looked like one I took off a 1974 slant.