I went to RealOEM.com, and the only difference that I could see between the standard R65 and LS version axle, was on the LS axle there is a step cut into the axle at the thread end, that the standard doesn't have. I couldn't see any difference in the '79-80 axle. But it wouldn't be the first time the parts catalog had it wrong. I went to A&S BMW, and Max BMW parts site, and both of them show the same picture for both the standard and LS, so much for that observation!