There are four distinctly different Baker hammer guns. There were the front trigger break guns made by Baker in Lisle, NY, as both doubles and drillings in the mid 1870s. By 1877 the business had moved to Syracuse, NY. Pretty soon Lyman C. Smith invested in the business and it became L.C. Smith Maker of Baker Guns. William Baker left and with some of Smith's relatives and the Livermores founded a gun company down on waterpower lot number 6 on Fall Creek in Ithaca, NY, building a Baker-designed hammer double with a top-lever. Meanwhile William Baker's brother Ellis started a forging company in Syracuse and in addition began making a trigger-plate action hammer gun on an A.C. MacFarland design, Patent No. 370,966. As originally built the gun had a dollshead and underbolt. William left Ithaca and joined the business in Syracuse. These guns were marked as the New Baker and made by the Syracuse Forging & Gun Co. In 1888 the plant burned and Ellis relocated his business to Batavia, NY, and as William was dieing of TB they brought in Frank A. Hollenbeck as plant supperintendant. Fairly soon after the move to Batavia, the company name was changed to Baker Gun & Forging Co. As the trigger-plate gun evolved it lost the dollshead and underbolt and got a wedge-bolt thru a rib extension. The last of these trigger-plate guns were marked Model 1896 on the trigger guard. In 1897, Baker brought out the Model 1897 hammer gun which was essentially a hammer version of their sidelock hammerless gun. They were offered with either Twist or Damascus barrels. I've always thought they were a pretty nice hammer gun and would like to have a nice example, but a really good one has so far eluded me. It seems to me that 1897 was pretty late to be bringing out a new hammer gun, and as few as I see around I don't think there are a lot of them out there.
In their fine article on Baker hammer guns in The Double Gun Journal, Volume Nine, Issue 2, William Furnish and Daryl Hallquist show hammer gun production ending at Baker in 1911.