I thought all the late HR Zed's had Sat Nav fitted;
Even a base model car had Sat Nav I thought, I haven't seen a late model without Sat Nav.
Sat navs have always been optional and is still the case on the 370's, unless they are the special editions eg Black Edition.
To my mind the car is definitely as stated and I see he also has a 2006 coupe for sale that does have more question marks against it, IMO