A Body Disc Brake Swap 101
The spindles can swap side to side to place the caliper either to the front or to the rear but the 73 system came from the factory with the calipers to the front. Folks mount them to the rear on the 72 down cars so the caliper will not interfer with the factory sway bar, 73's had a different mounting arrangement for the bar so it didn't interfer.
You need to swap caliper to, the key is the bleeder must be at the top, if they are below where the hose fits then you will never be able to bleed the system completely. If you are going to have the caliper to the rear you can't use the 73 style brakes hoses, they are not long enough and will bind with the wheels at full like and will fail quickly. You will need hoses for a Volare/Aspen disk brake car.
The upper control arm is right and left too. If the little dimple in the control arm for the rubber bumber on the frame to contact is not over the bumper then you have the control arms on the worng side.