Because you wouldn't just call a stock BOV a BOV, you would need to know whether it was 1G, 2G or 1G crushed, etc.

The stock DV's Audi's come with are garbage and can't hold more than 15psi, similar to the stock 2G BOV on a DSM. Their part number is 710N and that's where it gets it name from.

Therefore, most people who don't want to buy an aftermarket DV end up going with the upgraded version of these DV's found on the Audi TT and most Porsche models which is the 710S which is capable of holding much more boost and is less prone to fail; very similar to 2G guys swapping out their BOV's for the 1G equivalent.