I just checked Impala Bob's and they list a tool for pulling the spring out to the headlight ring. the spring for my impala just twisted into a hole in the body. I used a pick tool that has a tight hook on the end for hooking the spring in.. ..can be a challenge but persist and you will get it. on my car I had to do it 4 times. last one was easy...ha ha

this is the one that i used

 

The bottom just twist in till it is secure. 

Hope this helps 

Cliff 

Well here is what I learned...

I think the factory had a tool for pop riveting

those springs in.

I think people repaired them with regular 

pop rivet guns from behind??

I went with the bolt and nut fix

not factory but very effective with no hacking.

As far as the spring being straight...

the springs I bought were bent like the one in the pic

and they worked fine.

90 degree hook pick tool worked good for hooking the springs 

into the headlight retaining rings.