I too believe this is a correct, Holley H-1 carburetor used on 1912 Model Ts. The H-1 used this type of a fuel inlet. These are hard to find carburetors, especially for someone correctly restoring a 1912 T. The L-shaped fuel inlet pipe is usually missing and is hard to find. Also, it is hard to find an original intake manifold that hasn't been drilled full of extra holes. This is certainly a valuable item.
Here is a photo of one on a Model T as well as a link to the Model T Ford Club of America's encyclopedia showing the carburetor.
http://www.mtfca.com/encyclo/Hol12.htm