lol, i'm in the middle of DIY'ing a new top this weekend, and broke that exact piece on removal of old top (passenger side).
Re-ordered replacement for both sides (in expectation of maybe breaking again on re-install.
Passenger side is: 986.561.560.01 (may have a superseded part num on the last digit)
Pelican calls it a "Clamping Piece":
https://www.pelicanparts.com/More_Info/98656156001.htm?pn=986-561-560-01-OEM
(looks like yours is the driver side in the pic):
https://www.pelicanparts.com/More_Info/98656155901.htm?pn=986-561-559-01-OEM&bc=c&SVSVSI=0782