And if so, what brand/type were they?
They look like/are speaker covers and I use them as speaker covers for small speakers I bought and installed in the factory size holes in the console. My point is if you really care about music and sound you buy what size you want and cut them in wherever you want. If the GTV is more important than the music then you use the factory holes and speakers that fit those holes. Unfortunately, a PO had speaker holes cut into the rear parcel shelf on my GTV. One day I hope to fix that flaw. If I were to totally restore my GTV I would likely have no antenna or radio or speakers.The 1750 console had speaker-hole blanking covers only. Which seems odd if you don't know the brand/shape/size of
your yet to be purchased speakers! I can't help think that they were actually also an aid to connecting the console & wiring on the car assembly line.