Nice find again Joe!!
I see that 3400 is an early model. I have never heard, date wise, when they made the minor changes, which aren't very noticable. First thing I noticed, it has the small screws and rod for the rear antivibe. Another thing I have found on one I have, is the oil cap is different also, and won't interchange, at least on the one I came across.
Only other things I was able to find was some extra strengthening in the boss's for the antivibe areas, and a spot or two in the crank case, on the later ones.
Good lookin saw!!!
Gregg,