1970 Challenger Fuel tank question

Apologies in advance for a potentially dumb question - my 1970 Challenger (build date Sept '69) does not have a hole for the vent tube on the fuel tank. It just has the level sensor/pickup hole on the drivers side and the fuel filler hole on the passenger side.
On these early models, how did the fuel tank vent work or did they not have one?
Author: Dodgey