I just purchased part # 17879061 from GMC Pauls and could not be happier. They are perfect. No slamming required. They indeed were redesigned to make them ultra pliable as to avoid slamming the door. Only $51 for the pair. I was about to try the Honda seals others recommend, glad i didn't. GMC Paul's service is outstanding and he is a forum member as well.
https://gmcpauls.com/Pickup.htm
"67-72 NEW Push-On Door Opening Weatherstrip NEW WITH MITERED CORNERS Rated #1 Customer Favorite
The 1st & #1 Supplier Of Premium Quality Push-On Doors Seals for the 1967-72 Chevy & GMC Truck Community Since 2002