They have different part numbers 021 906 265 R and S
-S is for the 16v
-R is for the 8v
plug's the same, so if you have it just give it a try... just make sure cable is the same length (that will be the main difference).
I had an Audi 80/100/S4.... knock sensor fitted because it was cheaper than the one with correct p/n... cost half as much and only difference I could work out was a longer cable on the Audi one...