Yes, that is an aftermarket, 129-style wood kit. I have never seen this avaialble for sale in the US by any vendor, but there are a number of vendors in Europe that sell these. I beleive that a couple of our non-US members have this (or have had this) type of wood installed in their cars, but I can't remember who, and it's been several years since I saw photos of the car(s) that had this installed.
Hopefully some of our European members can respond with the vendor(s) in Europe who are selling this type of wood for the W124.