Mr. Dburb
I ran into the same problem with both of my rear springs, everything was oval. I replaced the cast parts and new springs. To hold them on I used grade 8 button head bolts. They look like rivits except for the place the allen wrench fits.
Now, rivits should be used since all the space is taken up when they are smashed, and no chance for movemet.
Most of us do not use our trucks for daily drivers, I dont, and have not had any problems.
If you use your truck frequently you could check the torque on the nuts, but I think you find they will work for you.