Vented Gas cap or Not for 1971 Charger RT

[71 RT]

I need you experts out there to help answer something for me, please.  Did the factory gas caps for 1971 Chargers have a vented gas cap, or non-vented? 

The 1971 charger had the 4 lines coming off the fuel tank going into the emissions container, and other strange fuel separators next to the fuel pump that vent back to the tank, but I am confused as to the cap.  Vented or Not? 

And if it is supposed to be vented, and it is not..... could there be a vacuum build up after a few minutes that could cut off the flow to the motor, thus causing it to stall for a while (while the vacuum releases) and then it drive just fine for a few more miles?   

Hope one of you out there is a "Vented gas cap" expert.  Please advise!  And thanks for your time...

71 RT