I believe as far as revolvers the Lightning Model of 1877 (though fixed cylinder) might be one of the earliest having been manufactured from 1877-1909 and available with barrel lengths 1 1/2, 2, and 2 1/2" according to TBOCF. I'll not include the deringer, old line nor new line handguns manufactured around the late 1870's as I believe you are asking about double action revolvers. So, yes they made "snubbies" prior to 1900 anyways . The above is taken from reference material as I've never seen nor held the above in person.
I am sure there were a lot from other manufactures. Colt made the The Colt Model 1877 in .38 and .41 Colt (the so-called Lightning and Thunderer, respectively) It was available in a “Storekeeper’s” version with 2 1/2-inch barrel and no ejector rod assembly until 1909. Then there was The New Pocket Revolver that came in blued or nickel finish with hard rubber stocks and a available 2 1/2-barrel. Then there was the Pocket Positive in 1905. I am sure there were others.