Missing rubber part in rear door

[kave]

Today I discovered that small rubber part was missing from the rear door on my T6 Beach. It is marked on the left side of this photo. On the right marking is the rubber part installed.
Is it a necessary part and if so what is the article number?

 

[Loz]

Some remove these to drain any water from building up, especially if you had a loose brake light issue.

 

[jts46]

Never had them on mine

 

[Daren_Chambers]

I'm pretty sure they are drain plugs and should not be there.

I had a few missing on my beetle (looked exactly the same) and I spoke to the dealer who advised they should have been removed as part of the dealers pre delivery inspection.