gas cap vent

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I finally dug out the repro gas cap I bought from Irv Blonder 25 years ago and comparing it to the original it appears to have no method for venting. I have been using the original (rust and all) up to now and found there is a tiny hole drilled into the screw holding the assembly together that communicates with the sheet metal insert with four holes that looks like it has an air gap to the cap that communicates outside air to the screw hole. The screw hole in mine was filled with rust so plugged and probably not venting.

I am wondering if others have had this issue? I don’t see much way to provide venting on the new cap except by intentionally splitting or otherwise preventing the cap from sealing.

If the cap doesn’t have a means to vent then I think the only path to bring air in as the fuel level drops is through the King Seeley vent tube that goes down to the bottom of the sending unit and would end up sucking air from the vent tube into the air dome and then through the tiny hole at the bottom of the KS air dome into the tank. The  hole is extremely small even if not plugged and could create negative pressure in the tank and fuel starvation/vapor lock. It might screw up the KS gauge level as well. 

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