That’s me. I had Roger make those PCB’s for me. Still available if you want it.
It’s the EE77 circuit. Totally different than the KA Electronics one.
The classic EE circuits are not the same as putting an HPF on the side channel. Both methods look the same on paper. 6dB/oct roll off on the side channel. The EE circuits don’t use an M-S matrix and sound different than using that method..