Is the Currency Converter available in maemo.org the same as the one in Ovi Store?

No. While we are the authors of both of the Maemo versions of Currency Converter for the Nokia N900 and they share a similar base, the version available in Ovi Store has gone trough a complete overhaul and is much improved compared to the old version in maemo.org. Furthermore, we now use our own servers for exchange rates updates. Because of this, we can now have more than twice the amount of currencies and a more reliable update service. Please read more about this here.