It is not the well-known Uldum logo, but it is indeed a legitimate one (I'm guessing an earlier version). Here is a link to an Uldum table that shows this logo in both label and burn mark formats:
http://www.auctionflex.com/showlot.ap?co=2887&weiid=5900298&lang=En
However, that chair doesn't look similar to any Johannes Andersen design that I am aware of.
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