Old station wagons

Old station wagons usually have two-part tailgates. The upper one with window lift up before the lower one drop down. On the sixth season of original "MacGyver" TV show, MacGyver got a 1957 Chevy Nomad from his grandfather who passed away and he can open the lower part without opening the upper part. How is the possible?

There is a seal on the rear drop gate that seals against the window. The two latch together, with the latch in the drop gate and the striker in the window assembly. It almost would appear that one cannot open the rear window without first opening the drop gate. This post (https://www.flickr.com/photos/mlgolfphotog39/8253066961) has a pretty good image of the setup.

-Rod

Aaaand, the penultimate of two-part, or 'clam-shell' wagon gates...!

https://www.youtube.com/watch?v=Ouo2HMmdSms