If the stickers are new, we'll learn this as well. Someone will come forward and say, "I know Cesar. Those stickers weren't on his van a week ago."
People on Twitter are claiming to have seen that van since at least last December, FWIW. You're not going to forget a van like that.
The images in the side windows appear to be posters that were professionally produced. They haven't been in the windows for very long. The sun would fade them relatively quickly. There is sun resistant paper but it isn't cheap and he probably wouldn't know to ask for it..
IOW, that’s what his handlers are saying. The only reason to say that is to establish he may have been a Trump supporter for longer than last week.