Sounds like you have a bitsa

Don't worry about the steer motor date, these do get replaced on older Reflex.

So the mast looks like it was made 29 May 2008 according to the sticker, that is possible, masts are easily swopped on these.

The electronics & dash fitted on this Reflex date it pre September 2004 while the serial number on the data plate date's it to 2003 production.

I wonder if the serial number on the data plate is even a Reflex?

Might be worth ringing BT / Toyota up & asking the service desk nicely, just say you rang up to let them know you have bought this truck in case of future BT safety campaigns.