...and yes, the VPI 9, and 9Sig uses the same Mint protractor. The only difference between these 2 arms is the wiring - Nordost for the Sig, and Discovery for the regular one.
Stringreen
While you do use the same protractor for both the regular and the signature JMW 9 arms, there are other differences in the two arms than just the wiring. A different arm wand, fine adjustment for VTF, and an oil damping well too.