BBS RS Center nut - Genuine?

Hi,

I bought some center nuts a while ago, here is a picture :

http://img502.imageshack.us/img502/3959/bbsrsk.png

Are these genuine? not sure if you can tell by the shape, they are 30mm height type.
Inside they all say BBS Made in Germany, plus have those 6 digit numbers like 09 24 013

Now notice the following ones, the edges are flat not curved :

http://img526.imageshack.us/img526/3709/bbsrss.png

I don't know if there's 2 types of nuts, but the ones i seem have sharp edges, these edges
look curved.  Look closely mine on the edges of each side of the hexagon, are curved,
where others i have seen the edges are straight (as in flat surface on edge not curve),
or is there just 2 different types of genuine ones flat and curved?

Are the genuine ones Aluminum or plastic, cant tell if it's aluminum or plastic the nut but i got a reason
to believe they are plastic the ones i got sold

Thanks.