I actually think I saw advertising lit for the 920 as Jonsereds and Jonsered. By the time the Husky-influenced 930 came out, it was Jonsered.I believe the dropping of the "s" occured sometime in late 83. I have an 83 490 that is a Jonsereds and a 84 490 that is a Jonsered. As Kevin said the 910 was the first of the 9XX series and are true Jonsereds and I think some of the 920s were labeled Jonsereds but not all and I think all the 930s were just Jonsered. That is how I understand it anyway.....and I could be wrong!!!
The rear mounts aren't really that bad.....they mostly fail if one gets the saw stuck in the cut an trys to remove it forcefully by yanking rather than lifting the log or cutting it out with another saw........or what ever it takes to relieve the stress on the bar. One just has to be very conscious of that fact......Other than that they actually do a pretty good job at AV duty....
Yes, the AV system is good on the 910 to combat white knuckle. As Robin said, don't yank on the trigger handle if the bar is stuck.
Kevin