Sometimes you will find the build spec on a sheet of paper tucked underneath the carpet under the drivers seat - worth a look ?
But you could consider these 2 other options?
1. Ring up VW HQ customer relations in Milton Keynes. I'm sure if you quote the VIN number to them they will tell you what the original colour of your car was when it left the factory ?
2. Let's be honest- at that age it's likely that your car's colour will have faded - a large reputable re-spayer will use an electronic colour analyser to determine precisely what colour your car is now so it's not too important to know what the original colour was since it won't be that precise colour now ? regards, yt.