One of my wery old NOS 1,7 (VW411) heads have a flexible ring on each valve stem named "oil deflecting ring" in Haynes manual for the Porsche 914.
The official Porsche parts list has no ring on the stem.
I guess the rings are for reducing the amount of oil going ito the valve guides but since they were left out later i guess they did not help wery much?
/Lars S