I had some concerns when I read that the coating on the watch was different from the DLC coating on the black space which is apparently indestructible (I had series 3 for 6 months and didn't even notice the slightest thing about it.
However, the target version goes through another process called PVD and is not as strong as DLC in space.
Just to complicate things a bit more … PVD (Physical Steam Deposition) is a METHOD of coating, while DLC (diamond-like carbon) IS the coating itself, so the two are not as similar as you compare method and material.
Which has led me to believe .. it may be that the gold watch is also DLC coated, but I don't know enough to confirm. [1