@@ Techman!! Your question is interesting!! Few years back, i bought a car, along with the all documents!! Indus motor gave me an original invoice, that was in my name!! At the bottom/middle of the invoice it was written that "This car is made in 2005" This is the best evidence. I am not sure in case of honda or suzuki and also in case of leased car!! but i think at the original invoice of honda and civic, this thing is also written!! You must ask from the owner to give/show you the original invoice!!
I will check my registration book!! i think, manufacturing year is also written on the book!! irrespective of registration date!!
Befoer booking for my new xli, i was also looking for the last model of prevoius shape of civic that was 2006 ! i am quiet confident that honda civic previous shape was not made after 2006!! In your case, the car could be of 2006 but registered in 2007. You are lucky if u geting this one which was registered in 2007! becoz, registration also matters in resale!! Model ofcourse remain of 2006, becoz, i guess shape changed in late 2006 or early 2007!!