Here's the Stihl repair guide if you think it will help.
I've used these studs a couple of times and they've worked just fine so far.
We had one customer come in with a MS 211 (single stud mount) and every time he took the bar off the whole stud came out with it. He thought this was normal. The way we found out about it was he wanted a new bar and needed "the bar with the nut and bolt already attached" and all the bars he's been looking at didn't come with the stud and nut.
I asked him to bring in his saw so I could look at it and he had his wife go to his truck and get it. She handed the saw to me and the bar would rock back and forth on the stud. Ever so slightly.
Somehow the threads on the stud got damaged right next to the bar and the stud and nut were loose enough to spin on the bar but the nut was tight enough to spin the stud. Of course the stud hole was too sloppy to screw a standard stud back in it so I used an oversized one.
Once I explained all this to the owner his wife gave him that "You dumb S@#t" look. So, feeling bad for the guy I quickly told them "Don't worry, this happens a lot." He smiled, the wife calmed down, and another satisfied customer walked out of the shop.
Good luck on your repair!!