The four bolt base is 1938, the two bolt base is 1939. The 1939 also has a painted ring with an extra shade for the license lite lens at the top, the 1938 has a stainless oval ring.
They are the same - just the position is different.
The coupe handle has a longer shaft than a sedan.
Deklite seemed to be stamped only on the bases for the USA.
The export ones from Canada that came down here to New Zealand did not have that stamping.