Internet Worm Protection Signature File revisted

I just have a follow up question regarding Internet Worm Protection Signature File

I have the latest one, dated 1/13/09 I believe. However the number of sigs I have is at 1,257.

I see others have 1,300+.

1.Is the difference that I'm using NAV2008 and the number of sigs differ because of that? That some of the same sigs get bundled for me? 

2.Does that mean Internet Worm Protection signature-wise that I'm not as protected?

 

Just curious