Pivot Shoes

As the shoes broke and left windows disconnected to balance shoes, they simply fell out, no screws have been seen. There are no major roads or trains within miles, so they didn't vibrate out. This is a double wide mobile home, it was supposedly built to to order at specs of a new house, but I suspect there may have been no screws at all. So which screws would we order?

Thank you for your time.
Pamela B.