I went to install my new JD needle and the first ting I noticed after opening the carb was the needle holder was different. Instead of an Allen head, it was an 8mm brass nut. So I took it out and the stock needle came out with it. I had rejetted my 250X and this didn't seem familiar. Being a jetting and overall mechanical Noob... I was a little concerned.
Turns out (thanks for the info Ken!).. that the needle change is simply to make removal from the carb easier. Otherwise, the needles are the same and work fine. Only notable difference is that you need to remove the clip off the stocker to get it out of the holder.
Here's a side by side picture.
