No, even more retro than playing your first game of Minesweeper on your first (office) computer. The design of these Minesweeper postcards uses the very simple occlusion technology so favored by lottery tickets around the world.
Myself, I used to get all excited about the scratch-off Pac-Man cards that came with sticker and a token piece of bubble gum. You had to uncover dots and power pellets to get all around the board without uncovering a ghost.
So while everyone else dwells in fear of which video game will next be converted into a movie, I'm wondering which could possibly be reinterpreted as a scratch-off game. Hopefully on a postcard, of course.