Junkmonstor mailed the signs just well enough to save from high shipping charges but keep everything intact.

Just like military surplus, they were mass produced but built just well enough to last many decades. Again, definitely produced under contract to some particular specification. There is the slightest amount of overlap, and the overlap was performed correctly so that you can see a slight difference in relief (5 mil or so) between different colors. It probably started out as 18ga sheet metal, was sheared and drilled, and probably three patterns were sprayed on to yield a full sign. I got one of the smaller galvanized steel signs from junkmonstor, You can see how the thing was put together.

These signs look very mid-century government contract. These days, the black portion might range from gray to brown to white depending on how long it has been left out there. I grew up seeing these all over the place, and by the time that I was a kid, they weren't faded, but they weren't fresh either. I bought one of these for a fallout shelter that I am 'rehabbing' for an older couple. Ebay just called this review a 'potty mouth' as I was typing the review?

Fallout shelter + sign