Hold off valve for 69 Nova disc brakes?

[Bill Rose]

I'm starting to get all the power disc brake parts together for the 69 Nova, to go from 4 wheel non power drum, to power front disc/rear drum brakes. I know there is a metering valve, and the distribution block in front/under the master cylinder.

What I don't know, is there suppose to be another valve (hold off valve) on the frame rail under the driver side door? I know my 69 Camaro had that hold off valve, but I'm not sure if the metering valve by the master does that job, or do I still need the hold off valve on the frame.

I can't find anything in the Nova assembly manual showing this hold off valve.