I have a 70 Barracuda
Spindles are made to be left and right, not interchangeable (though you can install them on the wrong side). Calipers to the front. That is the reason your hose doesn't fit right. My car was done incorrectly and thanks to the good people here at CC I got them flipped and all is right.
Yes and no. The factory designated specific part numbers for left and right, so to be factory correct they are designated to a specific side. However, the spindles are built symetrically and can be swapped side to side to change caliper orientation from front to rear. Different cars had them in different locations and other suspension items may have dictated original placement.
However, as explained earlier, swapping spindles side to side also requires re-orienting calipers so the bleeder faces up and may also create issues with hose and line routings. So it all depends on if you want it to be factory correct or not, if your retrofitting or just replacing. Both ways are functional.