There were two styles of moldings and clips used for '55. The first type was a carryover of the ones used in '54. Molding pieces telescope into each other on the second type.
These two places may be able to quote per sample on the clips:
The part numbers for the Clip, Windshield Reveal Molding, Side-lower are:
4651218 first type, right
4651219 first type, left
4658444 second type, right
4658445 second type, left
The second type were also used on '55-56 Oldsmobiles.
Here's a link to the Fisher Body Service News discussing the '55 series 40-60 windshield moldings.
Included are some pictures of original moldings and screws.
Here's an attachment showing a '55 dealer service bulletin on the moldings. All screws seem to be a short sheet metal screw, whatever size uses a 1/8" pilot hole.