Help identifying classic headstock part

Ramszhorn

Hello to all, I am new here and am not an expert in bikes, more a restoration enthusiast. I am currently restoring a classic 80’s Peugeot racing bike. I was about to re attach the forks and I’ve got a piece of the headstock which I’m not sure about. It’s a whitish plastic ring which does fit snugly over the fork stem. Although I’m not sure where in the headstock order it should be. Any help much appreciated. I will try to upload a picture if needed. Thx
http://i648.photobucket.com/albums/uu20 ... 9BE05.jpeg
http://i648.photobucket.com/albums/uu20 ... 611A4.jpeg