I've been having a think about this and i've come up with something that may be a nice solution :
https://www.ebay.co.uk/itm/FIRE-RETA...53.m1438.l2649
The felt was probably intended to emulate suede way back when the 164 was new so that might be a very good match for what you're looking for. If you're revamping the leather seats and making them look new as well, some new magazine/map pockets wouldn't look out of place despite the car being nearly 50 years old.
I don't know about anyone else but i for one would like to see some photos of this original 6-pot Volvo - if memory serves the 164 was the first 6 cylinder Volvo had produced?