Kurt: I have a pretty good collection of old Conoco gas station photos, and I don't think your pump would have been a Conoco pump for two reasons. First, the decals and signs used in the 1930's would have looked like those in the two attachments - either round decals for Conoco or Ethyl, or a rectangular decal for Bronze gasoline. Second, Conoco did not buy National pumps and I have seen exceedingly few Conoco photos with National pumps....so it is also unlikely from that standpoint too. Sorry that I cannot help you identify it....but I can probably rule out Conoco.