Zenith Carb markings

[Flyboy1st]

I bought a 1929 Coups about a month ago. It has a lot of the original parts on it. Looking at the zenith carb the upper body it is marked with an "Z" but the bottom half has no markings. All of the Zeniths I have had over the years always had Zenith 1, 2 or 3 marked on the lower half. It uses all Zenith parts and otherwise looks like a Zenith 1 and 2. Any ideas why the lower half is not marked?