I have one identical to this except it has a brass burner and cone. The plain cone uses those nubs on the burner gallery to achieve a nice friction fit. Keeping-in-mind that interchangeable parts cannot define the lantern, I believe your steel burner is original and could have had a cone with the drop-and-turn lock channel (like shown by Willis) and fits-in with the Dietz transition to steel burners that continues with the change to the steel winglock cone burner in 1909. Therefore, your lantern meets all the qualifications to be 1908. It also appears to be the last lantern that Dietz made with the old soldered pan bottom.