Since I literally wrote the book on the subject - Robots in American Popular Culture - I get to say, not by a long shot.
A case can be made for Charles H. Bennett’s The Surprising, Unheard of, and Never-to-Be-Surpassed Adventures of Young Munchausen in 1865. The young genius inventor first produces a robot schoolteacher and then a full household of robot servants. These are just passing mentions among his hundreds of inventions and play no major role, unfortunately.
I believe the first modern robot appeared in 1868, in Edward Ellis’ The Steam Man of the Prairies, a dime novel, #45 in Beadle’s American Novels series. The Steam Man was a powerful robot who could act like a locomotive but didn’t need tracks, so a carriage could be pulled at high speed even where there weren’t roads.
Many more steam men, and in the late 1800s electric men, followed in dime novels and in magazine story weeklies.
By the end of the century, robots were regularly appearing in stories in the better mainstream magazines.
Even if you don’t consider the 19th century modern fiction, consider that Tik-Tok didn’t appear in 1907. My choice for the first truly modern robot novel in America - a style of dialog, constant action, and cliffhanger chapters rather than Wells’ plodding paragraphs in frame stories - is William Wallace Cook’s A Round Trip to the Year 2000; Or, A Flight Through Time, serialized in 1903 and then published as a book. This utterly remarkable tale is a satire of a future in which robots have replaced workers, who are suffering “a demoralizing expenditure of idleness.” Kurt Vonnegut wrote essentially the same book in his first novel Player Piano, from 1954. Cook, who followed the book with many more serials and was in every issue of the leading pulp, The Argosy, for about five years, is the unsung founder of all American science fiction.
Baum had a huge number of examples to copy, including himself. Few people consider the Tin Woodsman a robot - rightly, since he’s more properly a cyborg with a human brain - but almost everyone forgets that Baum put a giant mechanical man in his very first novel, Adventures in Phunnyland, a pre-Oz failure. The cast-iron man is a minor character who appears in only one chapter and historically a footnote.