Vw golf gti campaign original under seal help.

Hi,
Sorry if this has been asked a 100 times already but my shell is at the painters and a question has been asked what product to use to protect the under side of the car and wheel arches. 
The idea/plan is to go to as close to original as possible, parts permitting. 
Does anyone know what product would've been used on the factory line in wolfsberg and would it have been primer, paint then underseal? 
Thanks 🙏 

Try vw original stuff part no is d003500 it's put on over the primer and can be painted over

Thanks much appreciated. I've seen a lot of people using the raptor which seems to a modern way of protecting the underside. 
Learning curve 👍

From what I have seen raptor can't be put on as thick as the original stuff is.

Do you know the product or part code for the protective material that's used on the sills? Seems different to the underseal. 

The original VW stuff put on the MK1 is no longer available,  the stuff VW use now im told is no where near the same standard,  i was looking into this and 3m Bags are what seems to be highly recommended. Raptor… seen a few people where they have had this not stick and starts to come away.