What is this on my end link spline?

`99 4Runner, bought replacement end links and there is this wrench (?) on the spline. I sure it helps when installing, but if I use it to hold the spline while installing, I'll have to leave it on? Also I thought there would be a bushing or something on the sway bar where the end link goes through the eye, but that means the swat bar will be bearing on the threaded portion? Or am I missing something?

Thanks in advance!