Good to hear from you again!
I sort of agree with CC here, but the key to all of this will be to be absolutely sure there is no moisture (and never has been any moisture) inside the core of the board.
If the board is stored at - 40 deg. in Wyoming, even with the vent opened, any water inside will freeze and this could cause delamination.
If your friend has access to a vacuum pump, it would be a good idea to remove the vent plug, make a fitting to fit and put a partial vacuum on the core of the board to "boil off" any moisture. I can get you the "safe" vacuum levels if you send me the descriptions of the boards.
Keeping them in bags would help a little, but in those kind of temps you get "cold soak" that creates things like the permafrost in the Yukon and Alaska so in an unheated shed
the temps will really get down low, even in bags.
You are correct, it won't hurt the carbon components, but if there's a way to get the boards up into the attic or somewhere warmer, it would be better.
Vents need to be open in any case.
Hope this helps,