JBL SE408S crossover/equalizer board for Paragon DD44000

I'm searching for the technical information about the equalizer board for JBL SE408S amplifier, to drive JBL Paragon with active crossover. It seems that the reference for the board is M20, but I’m not sure it is this one. Can someone confirm it is the correct reference?

Does anyone has the schematic with component values for Paragon (it would allow to create its own boards or to populate another board with the correct values) ?

It is amazing to see that JBL was already thinking active crossover at that time !
Help will be very apreciated.

Can someone at least confirm that the correct board reference for Paragon is M20?