Take a look at SWISCO product code 91-174, Phillips Window Latch Kit. This might be just what you are looking for.
If this is not what you are trying to describe, please send us photos to research.
A home owner says:
July 27, 2010
We have a seasonal 1970 Schutt mobile home on a lake in
Minnesota. The windows are original to the home. The bottom
windows slide up and down and have hardware on both the left and
right sides that snap into a grove to keep the window at various
openings. This hardware has broken on most of the windows can you supply us with replacements?