This particular car was registered in the UK in January 2017, so it is a fresh arrival - but is recorded as a 1962 build model and therefore entitled to this series. That means there must be some document to support it being built in 1962 (if there is no evidence of a build year it will be assigned a 'Q' plate and cannot have any other plate fitted). Is it possible it was converted later? Maybe by the military when required for use? On imported cars it is common to have the wrong years, but in the last few years they have become very strict about the years supplied by the person importing the car. On my Mustang I was required to show it was built in 2004 to avoid the dreaded 'Q' plate