Hi there and welcome back to mytoycars.blogspot.com! My entire Matchbox diecast collection is probably less than 100 vehicles, but in my collection I have a couple of these International Armored Cars.
I think I got these from some random toy warehouse many years ago.
I remember that there was this large cardboard box filled with all these loose armored cars. If I recall correctly, they were priced at 50 cents each. What's interesting is the white chassis because I don't think this model ever had a white base.
I think they were produced for some kind of company promo and that these were the extras/leftovers.
I would imagine that the company would have put their own logos on these trucks to be used as giveaways or something. Do you have any of these blank promo cars in your collection?