Hi,
I've owned a couple of these 60-66 c10's. I can tell you that there is indeed a left and a right. I know this is true for original style springs only. I'm not sure about aftermarket, but i can only guess that it's true for them too. If you clean, sand or blast the top of the hinge brackets (the flat piece that bolts to the hood) somewhere on those pieces you should see an L or an R stamped into them. Once you can identify them, this should solve your issue. Also, never, never do anything more than clean or wire wheel the springs, you'll weaken them otherwise. Anyone taking apart anything, remember to label the parts as they come off!! I know, this might not have been the case here, but good practice.
Good luck.
