1937 Nippies had wind deflectors and Robert Foreman’s image of an export Nippy (presumably from the wheel/tyre specification) clearly shows these, perhaps on a new or near-new car.
Gould’s book shows details of folding screens and several recent images have arisen of similar castings on cars dating from the end of 1936 onwards:
The green car also corroborates the standard design of the wind deflectors as these are present, attached to the holes where original equipment trafficators would have been:
Please make contact if you have any images which can extend the range of material shown here or present evidence of items supplied as original equipment.