The Gopro camera would have used an SD or micro-SD card to store the video.
I've seen SD cards that were immersed in water for two months or have fallen off the wrists of sky divers come up good.
The basis answer is that the GoPro camera memory is probably good and able to be recovered.
There is no indication of what model of Gopro cameras were used. There may be additional information, such as GPS history, on the cards.