TF original gas cap. Vented?

[roger55]

I bought this replacement original style gas cap from Classic Parts of America.



I've put in a new tank under the bed and moved the gas fill to the rear fender. It's the original neck and rubber seal.

The tank builds up some pressure and I'm concerned it might build up too much if this cap isn't vented at all.

Is the cap supposed to be vented? I don't recall pressure building up when I used this cap on the original tank behind the seat.