Nothing of value to add, but this thread brought back memories to me. I bought an 031AV in 1979 - used but like new from a guy who worked at the Hormel plant in Fremont, NE. I think the repetitive nature of his job on the line had caused what he termed as "holes" in his shoulders, and he just was unable to use it.
I used it a ton, and several years later (I want to say probably in or around 2005 or so) it just wouldn't run any longer. I took it to the local Stihl dealer and didn't hear anything back from them so I called. I was told that the031AV was never intended for the US market, and that he had no parts to repair it - that I could come and pick it up.
When I got there it was in pieces in a box and the plug wire had even been cut in two. I wasn't happy but took my box of saw home and at some point it just got sent to the dump.
All this predated my stumbling upon chainsaw forums. I often wondered after reading on here if I'd known about these chainsaw sites if my 031AV could have been fixed up.
Anyway - I told you it was of no value... just rambling and bumping the thread!