Rowler there should be a part number stamped on the aluminium casting around the pinion, probably under some dirt.
There's also a service sticker somewhere on the car that will tell you. On 1980 models I think it might be in the boot, on the back edge of the boot opening, near where the hinges are. It looks like this:
![Image description](https://cdn.ozvolvo.org/assets/files/2024-02-12/1707776687-75864-1331367versionlo.png)
If you do find this sticker, report what steering-gear code you have here and I'll look up what rack it corresponds to.