https://vignette1.wikia.nocookie.net/fallout/images/2/2d/Gho...
https://vignette1.wikia.nocookie.net/fallout/images/2/2d/Gho...
I don't know why they didn't do that exactly. I'm imaging there was some reason though.
I actually thought about that possibility. Figuring civilization will have collapsed several times, there's a good chance most people could look quite disfigured. I mean, post-apocalyptic wastelands can be harsh. At a minimum nobody will be exfoliating on a regular basis.
Then, if the meaning of certain common symbology happens to be reversed (e.g. arrows pointing away from the subject of interest), that's all it would take to mistake that image as marking the location of a miracle cure—a radioactive fountain of youth.
Regardless of how you read things you'd put those in the correct order since I'm fairly certain that the direction of time won't have reversed by then. It also avoids flipped meanings of glyphs like arrows.
They additionally convey a "contamination" of radioactivity that stays with the man over time.
http://www.wipp.energy.gov/picsprog/articles/WIPP%20Exhibit%...