Year ago, I've seen comparison between map of one of the tombs in WA and one of those 3 maps you're asking about, and it was almost the same . I couldn't recognize other two, but it was early when I got WA so I can't say they are or are not just decoration.
Unfortunally I couldn't find that website I saw that comparison, and find out I have problem with sets in game - I did complete reinstall of game and launcher accept explorers loot and tiki set as installed, but when I load the game they are not there. When I load launcher again, I can see them between downloads but they are not installed, so for now I can't upload pictures of them. If you took close photo of maps, I may recognize that map I've mentioned.
EDIT: I found the topic in Sims 3 official forum about it,
here is what I was talking about. I'm glad my memory is good enough to remember seing this year ago.
