How to tell if the springs were originally bare metal or painted black:

Find remnants of the original latex paint daubs on width of top leaf at 10:30 on left front spring eye, or 1:30 on right. This area is the most protected from the elements and road debris, but any latex is usually invisible until cleaned non-abrasively. If cleaning with fresh Evapo-Rust, only soak for 1-2 days to preserve the latex - more time will remove it. After checking for latex you can re-immerse the leaf for more rust removal, if needed.

Carefully check under adhering latex paint and on the back side of latex paint chips for black paint. If none, the springs were bare metal. The latex paint daubs would have been a last step in spring production, after assembly and any black painting.

My 160,000 mile springs had black paint on the top side of the latex paint chips, indicating a spring shop had painted them black, not the factory.

For original bare metal appearance of hot rolled, heat treated steel bar for leaf springs, use gun bluing followed by RPM. See:

https://board.moparts.org/ubbthreads/ubbt...tml#Post2454941

In my experience with gun bluing, the final color is more black than blue. Repeated wetting with solvents such as acetone or lacquer thinner and wiping with a clean rag will slightly darken the gun bluing.

Photo shows strut rods cleaned with Evapo-Rust, then cleaned with mineral spirits, and treated with gun bluing. The top one was further cleaned several times with acetone or lacquer thinner before bluing, and the bottom one was cleaned only with alcohol before bluing according to the bluing directions. Unfortunately the lighting was yellowish fluorescent.