I just know my own saw as a reference point, and try and judge from there. By knowing when another saw hit the market, I kinda know the # of years a change in the #s make.
I should keep more organized notes of it. For example, I don't know exactly when they stopped using the D cylinder in the 046, but it was between SN 138****** and 140******. Wish I had an exact #, but just little stuff I store in my brain.
I also had an 044 that started 120******, and I know that saw (and prior ones) had black control levers and the smaller (4 mm ?) recoil bolts.
His # is very early, so I was curious. Wish I knew the # they started with.
The problem is, some saws were recorded, some were not.
I think the SNs when the bolts changed, and the control levers changed have been posted, but I don't recall them exactly.