It depends on the specific XPS 13 (9333, 9350, 9360, 9370, 9380, 73xx, etc.).  On most of them the mount is part of the palmrest assembly -- or the palmrest-keyboard assembly on some of them.  That's what you need to replace -- the part in question is not available separately. If you need a part reference, post the exact system model.  
I need to replace a piece that attaches to the hinge of my XPS 13 notebook, I don't know the name of it though and its seems like the full hinges that I've found for sale don't contain the piece I need. I've posted a picture below. Anyone know the name or where I can buy it?     [IMAGE]This piece[IMAGE]which attaches to this piece    
XPS 13 spare parts hinge piece