I'm not positive, but I think that is the only (and BIG ) difference 
I've had two side by side, and had to count the splines to make sure I was putting the IFS ones back on 
but at the time I wasn't looking for the differences other than that
yes that is right the only differenc is the inner hub gear, bobylong make inner hub gears that will convert an ifs lookout to a SA lookout.
thats the way to go because you can easaly find ifslookouts
