If the baby is shipped with the recommended 40 hour heat pack, technically you would be fine...
That being said, my last snake was lost in the mail overnight, so instead of showing up on a Thursday at 10 am, she finally arrived Friday at 11am. The temps were much warmer tho.
I've been VERY unlucky and that's the 2nd time that happened to me. And I am always very cautious. I make sure that I have the ship day and the next day off just in case.
If I was you, I would humbly apologize to the boss. Explain the situation. I would hate to loose any animal due to poor shipping conditions. I'd wait til the temps warm a bit again.
Edit: hahah, you posted seconds before I did. Glad to hear you changed the date.