I know this is an old topic but I can explain why there is a gap if anyone is wondering. The stock ICS signal/data layout overlays the network and traffic arrows on top of the signal. However because Moto wanted to keep them separate like in Gingerbread, they had modify it. Unfortunately they took the lazy route, keeping them overlayed but making all the images twice as wide, keeping the signal right aligned and the data left aligned. So when data is off, that gap to the left of the signal remains there (because its twice as wide).
The proper way of doing this is to modify the signal layout xml, and specify that the data sits next to the signal instead of on top of it, so when its not visible it doesn't take up space. Not sure why Moto didn't do this, though it doesn't really surprise me.
Short answer is that you're not missing any icons, it's just bad Motorola coding.