The hatch glass sits in a channel in that "seal". It's a complex bit of rubber that holds the glass, fits around a flange on the hatch to keep the glass in place while sealing the top of the hatch from the elements. The "chrome center" is stainless steel strips that hold the weatherstrip in shape so it doesn't pull away from the corners.
Normally it's easiest to cut the existing weatherstrip to get it out of the hatch and use a new one to re-install the glass with the new weatherstrip. If the existing weatherstrip is still very pliable, you could remove it by prying it off the hatch flange from the bottom side of the hatch and pushing it (and the glass) up. It's normally not worth the effort it requires though.
These come from an era where the glass is not glued in like todays auto's. Maybe there's a YouTube video that shows how 1970's automotive glass is installed...
1974 "early" 260Z - L28ET - MS3X full sequential fuel and spark, COP=Ford 4.6 coilpacks w/ Nissan Ignitor, diyautotune chopper wheel - FMIC - T04E .63 A/R - 400cc Injectors (too big!), 14point7 Spartan2 Wideband - C/R 5-speed - Coilovers - Big Brake Kit up front, Porterfield friction all around. Mesa, AZ