According to my window sticker, Comfort-Flo Ventilation was standard equipment on a GS 455 - at least in 1970. The question is: does that "ventilation" include the vent on the far left (or both sides, for that matter) when the kick panel cables are opened? I ask for 2 reasons: I found this picture on a Buick Facebook page and can't recall ever seeing the delete plate on the left side of any GS's I've owned over the past 30 years. And here's mine: The other question is, is there a way to shut that vent? Pushing the kick panel cables closed doesn't seem to work.
This is my 70 Stage 1 and has the comfort flo Same vent and can't remember exactly but I thought it shuts with the top pull and I never saw a delete plate like that.
Cars with Comfort flo could possibly be both. The pic you posted is most likely from a non air base model skylark. GS cars were optioned even at base with the vent on the left as far as I can tell from my research. That said you could have had a base skylark with comfort flow because it only controls the lower kick panel fans and has nothing to do with the upper vents.
So does the top cable operate the top vent? Kinda makes sense if it did considering my top cable probably needs to be replaced. Pushed all the way in, that top vent still blows air.
To add a little more detail, if the car with vent windows (2-door post, 4-door post, wagons) has A/C it does have the vent on the left side just like the rest of the cars and kick panels with no pull knobs/vents. If a car with vent windows (2-door post, 4-door post, wagons) does not have A/C it got the dash cluster without the vent on the left side and kick panels with a single pull knob. Also, if the car is a 2-door post, the rear quarter panel skins are different part number because there is no big hole and plastic vent in the door jamb above the striker on the body.