Sprang, Elias, Kirby, Certa, Kane, Andru & Esposito, and Infantino were all involved in the original art stats that were used for the cover in 1961.
Jerry Ordway says: "As I recall, the editor sent the bad stats they had on hand, as well as a color zerox of the original comic. I think they had me change something on the Batman Superman part too. I drew it big to match the original, but layed it out to fit the paper I had on hand, knowing they would drop the shots in digitally. They instructed me to feel free to fix it up, but I tried my best to follow the color copy of the printed cover. The printed version of mine came out well I thought. I felt like I succeeded at what they wanted me to do."
I loved that old comic, and still have my copy of the first printing, but I bought the version Jerry did as well because I liked seeing his version of the art in addition. I've always liked Jerry's polished style of inking.
When I was avidly collecting vintage Silver Age comics, I could practically use that old SECRET ORIGINS as an index to let me know which original stories I REALLY wanted to have in my collection.
It looks like Jerry added some definition to Batman's abs and Superman's face, but I actually see more difference in the Adam Strange & Green Lanternpanels than the Superman/Batman one -- the Gil Kane faces in those two characters is somewhat different than the kind of face Jerry draws, and drew for the recreation. The art is a huge 12 1/4" x 23 1/2"!