1969? Are you sure. My first car was an F reg. Bought approx. a year old c. 1990.
I think the number plate was probably correct for the car, I don't think they're quite stupid enough to use a car with fake plates and if it was re-registered just for the show that would be easy to prove and might actually get him sacked this time. What I think probably happened is someone saw the car and thought "what a fab car to take to Argentina"