On my '64 Dart, the adjusters are mirror images of each other. I think the star wheel is always toward the back. If you look at the way the self adjusting cable is routed, the star wheel should be on the same side as the adjuster cable and lever. If the shoe moves out far enough, the cable raises the self-adjusting lever enough to catch a higher tooth on the star wheel, and then the lever rotates the start wheel down one click when the brakes are released. Rotating the star wheel down extends the self adjuster.
This picture is of the right front, which should be the same as the right rear, or a mirror image of the left rear.
The parts kits that I've bought recently have different self adjusters for left and right, because they should always be extended when the star wheel is rotated down. I would think that you could use the same adjuster on both sides of the car if you routed the cable backwards on one side, but you'd also need the matching adjusting lever. All the other parts should be interchangeable left/right (the cable, the half-moon cable guide mounted under the main spring, and the lever return spring).
You can still get these parts at Rockauto, and usually at Autozone or O'Reilly as well. Just be prepared to repeat the phrase "Drum Brake Self Adjuster Repair Kit" about 3-4 times before the guy at the parts counter manages to find what you're looking for and stops trying to offer you a brake hardware kit or god knows what else. It also helps to have the part number with you, which you've already looked up on RockAuto.