To me, they look like the little toy one that you buy at the hobby store for doll houses.
Here are a couple patterns for the real thing... -
A simple one - http://www.shawcreekgeneralstore.com/plans_adirondack_chair3.htm
More complicated - http://www.thingstobuild.com/adirondack-chair.html
They actually sell these chairs the same size at heaps of stores that have wedding favors. Search wedding favors or beach theme wedding favors on the internet and you will see how common they are to find - exactly the same. e.g athttp://www.icestandard.org/content/view/28/beach-wedding-favors.html or http://www.beachthemeweddingshop.com/wooden-deck-chair-candle-holders.html - they are actually card holders for wedding tables and retail for approx. $ 12 for a 4 pk. Hope this helps.