It was reported in contemporary news accounts that a sequel had been filmed in the Lake Tahoe area simultaneously with the principal photography for the first Doc Savage, but the sequel was never completed because of the poor box office for that first film.
To put out the fire in Doc's residence, "extinguisher globes" are used. In reality, such globes were marketed in the nineteenth century. They were made of glass and filled with water or some other fire suppressant. Though they had a long shelf life and are now collectibles, they were only minimally effective against fires.
Popular "sci-fi" author and pulp fiction fan Philip Jose Farmer wrote a book entitled "Doc Savage: His Apocalyptic Life", a biography of "the man of bronze". In it, he theorized that Clark Savage, Sr. (the father of Doc Savage) was James Clarke Wildman, who appeared in the Sherlock Holmes story "The Adventure of the Priory School". Farmer wrote an unused script for a sequel to "Doc Savage: The Man of Bronze" entitled "Doc Savage: Archenemy of Evil", in which Holmes himself made an appearance, commenting on Savage as the greatest student of deduction he ever had and referencing his encounter with Savage's father. It remains unknown whom Farmer wanted for this role.
Near the start of the movie there is a scene which features a Broadway Ticket Agency which is promoting a boxing match between Joe Louis and Max Schmeling. There were two matches between them in 1936. Schmeling won the 1st match and Louis won the 2nd.