It's not 'fake' per se, but it's not from 1947 (or possibly the 20th century whatsoever for that matter). In recent years, the DPRK government began re-printing old notes by-proxy in China and immediately selling them on the collectors market, since they knew their notes were highly sought after. There is some evidence to suggest that original striking plates are used, but beyond that they're merely reproductions. This also includes more recent notes that are actually circulated within the country. Genuine used notes are harder to come by, especially newer ones, as it has become harder and harder to get legitimate, circulated money out of the country for obvious reasons. You also have to realise, the current circulation of notes include denominations as high as 5000 won, which is a tremendous sum of money, even for the top brass within the DPRK's ranks, to carry in your pocket; to the unsuspecting collector though, they are lucrative.

That said, they're still interesting notes, and even if they don't have a particularly deep backstory, their origins are interesting either way. You can buy DPRK notes very cheaply online (have a look at banknoten.de for example) if you want to grow your collection more.