Thanks for the correct information - I have just checked my source, which is a well-known site, and they say the van is from 1949, and that Riva began trading in 1949, but then they show a photo of another Riva-bodied car from 1948. It shows that you can't trust the internet, and that websites can be contradictory with their facts.
I will change the title of the puzzle - you know far more than me!