Dude, welcome to my world, I posted about this ages ago and got no help.
Basically, I also contacted VW and a bunch of places and they all new sweet FA. They said the only way you can tell is when the springs are off the car

As brad says they fitted 1 spring type on early MK3 then changed, I thought I bought the right type but they were wrong so I had to get new retaining cups for the springs
The mechanic who fitted my new springs was sound about the whole thing, just told me what was wrong and what he needed
Trust me once they are on you will be a lot happier
