There are two different e-brake cable arrangements I'm aware of. One that uses equal length rear cables with a long intermediate cable that runs in a "U" shape and doesn't have a housing. On that arrangement each end of the intermediate cable is connected to the rear cables, one end on each side. The "middle" of the intermediate cable is attached to the housed cable that runs from the e-brake handle on one side and that J bolt on the other side in the front.
It looks like this on each end, one bracket on each side for each rear cable
View attachment 1716275932
And here's your J bolt, on the right hand side attached into the torsion bar cross member, holding the intermediate cable.
View attachment 1716275935
It fits into a slot in the crossmember, just to the outside of where the front frame rail comes in
View attachment 1716275933
The other arrangement uses two very different length rear cables and uses a cable that runs just down one side and has a housing. That version has both rear cables attached to the cable on the driver's side rear, with one end of the cable at the front of the car and the other at the rear.
This is what that arrangement looks like on the driver side frame rail at the back, notice the bracket is for both cables (only one is installed here though)
View attachment 1716275936
It doesn't matter to the brakes or the rear axle which arrangement is used, it only matters to the car. So if you have two brackets, one one each rear frame rail, with only one cable attachment you need the intermediate cable set up. If you only have a single bracket on the driver's side rear that holds two cables, you want the one without the intermediate cable. My '74 Duster has the intermediate cable set up.