Thanks for additional comments and more links to photos.
I wonder if the "No Tirar" on the side of some of the vehicles expressed the passengers hopes that the effectiveness of the boiler plate armor would not be tested.
At least one of the ACs (
https://img-fotki.yandex.ru/get/9358...8b79ca_XXL.jpg) appeared to be a rolling bunker with concrete protection. That would be an interesting texture to reproduce in a paper model.