Advise on buying a used jb4

Hi
Any advise will be appreciated
Looking to buy a second hand jb4 for n54
Seller claims its 1 yr old, car was sold is reason for sale
Going to look at it tomorrow
Advise required
Is it even worth it
If it is
What should I look out
Is there anyway to test
How would I tell the age
How many parts would it take to make it complete
Is there knock offs
Is so, things to look for
Pic given is below

Thankin in advance