I'm pretty sure I have some pics of it being made in the main resto archive, but no detailed documentation on how the guys went about it.
It's made of 3mm
plywood MDF, with a foam backed carpet glued on top, and
5mm 8mm of sound proofing foam on the bottom - that's as much as I know

Here's a close-up of the piping.
Edit: that's the only other pic I've found

There's a bit more details in my write-up on the custom speaker pods:
https://zv9485.wordpress.com/2017/09/09/installing-rear-speakers/As for the console, the entire trim job was sub-contracted by my restorer. Sadly I've no detailed archive of how these guys went on about putting everything together from the pre-cut patterns, bar some pics from the re-assembly process that just happen to include the new trim. The bottom edging is made from the same vinyl material as on the rear parcel shelf. This is how it all looks on the car:
