Wow Steve! Nice very rare-rare find. I would date this 1891-1895, the versions after this had SSS embossed in the fount top. Not having the fount embossed CTH CO No 0 like the steel ones goes, I think, to the brass material. These are shown in the 1891 Ham catalog as availabe in steel, polished brass and nickel plate (over dull brass). The burner on this is the right size (No.1, 5/8" wick) but not original. Your problem is the burner cone for this is unique; however, it is easily recognizable. Note that the lift on the SSS causes the globe to depart from the globe plate which is attached to the burner cone. This cone is a three piece assembly consisting of a steel cone base with a brass cone trapped inside and the globe plate attached. The whole assembly locks (drop-and-turn) onto two posts projecting from the burner galley.
I would like to know if you can see any other patents stamped into the burner gallery besides the Sept.16,90 and if it also says PAT APLD FOR.