Ethan,
Other than the photograph (which will not be of the specific animal), why do you believe this will be a bimac? As CaptFish mentions, we have a difficult time sourcing them because of the legal restrictions in California. The temperature range in the description is suspicious (60-79F). I am unaware of an octopus that can successfully live in the range given. 72 is the max a bimac should be exposed to and 75-79 is the temperature range for a warm water species. I would suggest you write and ask the specie ID as well as where the animal comes from. Since they also show wunderpus photogenicus (labeled mimic - Thales correct me if I am wrong on this one, I still have problems with the id), I suspect they receive Indonesian animals and this would NOT be a bimac and would need the warmer temps.
In short, the listings apear to be very inaccurate.