Define need. It goes bang every time without any conversion. If you bought it for what it is, you'll be happy.
However, if you want high-capacity magazines or a proper pistol grip then you need to convert it. This means reducing the foreign part count to 10 out of a total of 14 legally defined parts - but magazines count as three parts and a fire control group is also three parts so it's actually very easy to get it down to 10 foreign legally defined parts. A pistol grip and a new stock are also one legal part each. If this is confusing, use this handy calculator.
http://gunwiki.net/Gu