Sorry, not really. What I call the 'Lean burn' type have the (?) 6-ish mm, horseshoe shaped shroud around the atomiser and I've only seen them on 36's. The 40's, from memory, had two types of atomiser surround. One that didn't protrude into the Venturi and one that surrouthe atomiser orifice and rose about 3mm above the floor of the Venturi.
Sorry, that's all I've got.