I did a bit of an analysis of the Bosch ones a couple of years ago.
https://www.volvoforums.org.uk/showthread.php?t=324380
The same part is used on the Porsche 944 and some other models of the same vintage. This is a good thing because it helps to ensure a supply of reasonable quality parts.
The Porsche part has a very minor difference in the outer black plastic shield but the inner bakelite cap is the same Bosch part number. It is possible to transfer the original Volvo shield if you’re that OCD but I didn’t bother and my car has been running very happily with the Porsche part for the past couple of years.
As an aside, I happened to notice in my Euro Car Parts order history tonight that the Beru rotor arm I ordered for another 940 cost £16.24 in 2021 and is listed at £25.99 now. That’s some rate of inflation.