Speaker holes 68 Baracuda Notchback

I attached a photo of the back of my 68. Can anyone tell me what these two holes are for? The ones boxed in, in red.

I posted this on a FB page but have gotten a couple different answers so I’m just here double checking.

Also, no picture but the dash takes a 4x10 speaker that I want to replace with something more modern. Classic Industries sells a 4x10 and they claim that their version is the one that fits correctly. Does anyone have any experience with this? My car is an AC car.

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