My original IPLs of the 80/90 don't show the full-wrap. But my original 910 IPL does and with the heated handles. It's my understanding Magnus the Swede says none of the Jonsereds left the factory with full-wraps. That was contracted out in the States mostly through Tilton and Scotsco. That's why there is some variation in the full-wraps themselves.
I have both steel and aluminum full-wraps. I hate the steel ones; the palm diameter is too small and digs into your hands after a full day's work. If Tilton didn't list the 81 as a model they sold, then I really believe it's a Scotsco iteration with the aluminum full-wraps.
As far as the mufflers.....some of the West Coast saws had bottom louver mufflers. My 80 does and there were actually replacement louvers available from suppliers back in the day because I snagged two. I don't see them listed in the IPLs either all the way through the 910.
Oh and the unobtainium AV mount from the full-wrap back to the PTO side of the saws through the 910e was available through dealers at one time. Not listed either in the IPLs until the 910 and then it is. So the dealers always had a # for it, but you had to ask and then they usually called in for it..... unless they were Tilton or Scotsco. The last one I bought was from a dealer in the '80's....he informed me that one was probably the last one in the whole country. Pre-Internet, he had called several out-of-state sources, who told him that that was probably the last one.
In my 20-year+ search for that AV, I have found some NOS mounts. I don't wanna say I'm 'poor' with them, but I have a few. One was thrown into the deal with a parted-out 910....the Jonsered counter gal selling the parts had no idea what it was and threw it into the pot! And then Kevin from Saskatchewan went around NA looking/buying up old Jonsereds/Husky parts. He amassed enough parts to put together whole saws and sold them to collectors and on the Internet. He too had some of those AVs and had no idea(until I told him) what they were for.
None of this really matters except for posterity because most of the surviving full-wraps on Jonsereds saws have had that bottom PTO portion cut off and some bob/dangle thing stuck on the full-wrap. I've even had MANY collectors argue with me and say they came that way....Kevin included. But eventually, through his own research, he realized they didn't.
Kevin