jiminy,
I have a BVM viper that is very old. It does not have a "sawtooth" notch in the leading edge. However, as I recall the newer versions of the viper did in fact have the the sawtooth notch in the leading edge of the wing.

Mine is the very old version that does not have a hatch in the nose. I think that the newer ones also had a hatch up there as well.

As far as flight characteristics, I remember hearing a long time ago that these new wings help low speed performance but it's been a while and I might not be remembering it correctly.

Hope this helps,
Randy