Lightning has been the model name of those O/U with round knob and thinner, often somewhat rounded for ends since introduced in the Superposed decades ago. Gran, White, Feather, and whatever other added wording is added is used to designate other features to the Lightning model such as upgraded wood, silver receiver, alloy receiver, et al. The Lightning is generally considered a field gun though it has been used on occasional runs of "target" models over the years.
I'm not aware of any 16 ga Citoris using anything but standard Invector chokes though my familiarity with the newer guns ends around 2018 so there may be a change in newer models. The newer semiauto uses the DS system which is different than Invector+.
