This case smells like parallel construction. Oklahoma highway cops are pretty aggressive, but an out-of-state license plate hunch correctly leading to a big drug bust seems implausible to me. They already knew drugs were in the car.
I was pulled over for having out of state plates in middle america because they thought I had drugs just because I had California plates. They did a drug sniffing dog (before this was ruled unconstitutional). Cop was absolutely convinced I had drugs and so disappointed I didn’t.
What you’re not accounting for is all the people they pulled over that didn’t have drugs and you never heard about.