You have a pair of 'stabilizer bars" that rest on the head set to support the screen at speed.
Those pieces are shims but they do not stay on the bike. They are gauge blocks to adjust the space/preload of the stabilizer bars.
You insert those shims between the base of the wind screen, and the base of the kymco screen BEFORE tightening the stabilizers.
This moves the puig screen far enough away from the bike so as not to allow contact or vibration at speed. After it's all snugged down pull out the shims, and toss them.
I had a similar set up about a year ago on a BMW. The owner was Bat sh** insistent they were a part I forgot to install until he called the maker of the screen, and they told him what they were for.