I wondered that myself as this is the only car I’ve had with this type of setup. I assume it was put there because the firewall was cut out and moved back and the brake pedal is floor mounted instead of hanging under the dash. So the rod comes out of the front of the MC and attaches to the brake pedal. I plan on leaving that all as is. So I can keep the residual valve and plumb in a proportioning valve when I replace the lines in case it is needed. The front has wilwood hubs and discs and a mustang II front end. I will check the rears when I get back to the shop but I think they are aftermarket pieces as well.