Lex Hogan

I just got a Champion 400 fire pot and tuyere. All of the pictures I can find show a patent date like the one pictured. Mine has the No 400 in the center and no patent date. The lettering on the bottom is too eroded away to fully read but I can make out enough to know it is for sure a Champion. Unfortunately I cannot currently post a picture. My question is, does this mean mine is pre 1907? Any help is appreciated.