Date of Manufacture Question

[asuperglide]

I just bought a used 2006 E350 4matic. I was looking for this car for several months before I bought. The nameplate states manufacturing date of 3/06 and the title states 2006. I've see cars offered at 2006 with nameplate that went back to 4/05. Can anyone explain this and/or the cut off from one year to the next. Just wondering when the 07's came out to when mine was finished.