If you can't find the specific manufacturer's model, you can get a more general gasket.
We've done a lot of custom windows and use Trim-Lok gaskets which are the EPDM foam rubber - the same stuff on your car door. It's very UV resistant, and quite soft so compresses well. I'm guessing your application uses the D-shaped bulb - you can buy it on Amazon.
They have two adhesives, a BT and an HT. The BT is a 3M product that creates a moisture barrier and it is ridiculously strong - probably last for a decade. The gasket comes in a single long strand, so if you're doing a hatch or a window, you'll cut it to length, apply it, and have the two free ends come together (preferably where there is the least chance of water intrusion, on the top side of the window for example). Cyanoacrylate superglue is the best adhesive to attach the two free ends together to create a continuous gasket. Works best if you also buy the primer for the glue.