I have a '48 Chevy 1/2 ton 5-window deluxe with a 4-speed floor shift.

This is the retaining stud on the passenger side:

http://s160.photobucket.com/albums/...ky/?action=view&current=DSCI0035.jpg

There is an exact match to it on the driver's side.

They appear to be original.

1948 Chevy 1/2-Ton 5-Window Deluxe
More pix in the Bolt Bucket