<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MosportGreen66</div><div class="ubbcode-body">and cap

</div></div>
BTW, I believe that is the original assembly line cap as the later ones had an additional molded ring around that center relief hole opening.
Here's a shot of a couple caps from the garage. Newer style replacement cap on left, original assembly line piece on right.