1935 Ford V8 Locking Gas caps

[Ian NZ]

As far as I can make out this style of gas cap (as per photo) was apparently the correct one for Ford V8's from 1935 - 1939.
I have seen three versions of this gas cap, two with the wording stamped on the screwed on plate (as per photos) referring to the to the vent, one plate has three screws and the other four. and the other other more common type not having any wording on the four screw plate. I have seen two sold recently on Ebay for a big price, one was $177 without any wording on the four screw plate.
What I would like to know is this style of locking gas cap with out the wording stamped on the four screw plate in these 1935 - 39 years, can one of the screws be removed to change them into a ventilated type or are they already the ventilated type same as the ones now reproduced by Bob Drake.