You have perhaps forgotten the International Jonsereds Heritage Agreement that was authored by Taplinhill and adopted by all of us.
The 820, despite the fact that it was manufactured after the electrolux takeover, is indeed a "true" Jonsereds in that there was no corresponding Husky model. The entire 820/920/830/930 saw family are Jonsered only.
The 910 from which this model family evolved was introduced
before the Elux takeover, and is therefore considered a
pure Jonsered, as are all pre-elux models such as 621's, 49SP's etc.
Jonsered models that have a directly corresponding Husky model, such as the 2171 are considered
shared product.
(Thought you got me, didn't you?)