About PK04 BOO
Current style
PK04 BOO is a current-style registration, the format the DVLA has issued since September 2001. The first two letters, PK, are the memory tag, and P is the region letter for Preston.
The number 04 is the age identifier for March 2004, so this plate can go on any vehicle first registered on or after 1 March 2004. A registration can never make a vehicle look newer than it is, so it cannot go on anything older.
Private registrations move between owners through the DVLA: once a price is agreed, the registration can go straight onto your vehicle, or be held on a retention certificate until you are ready to use it.