based on what i know about batteries and how they are affected by heat and cold and doing a bit of googling and research i have come to the conclusion that gel batteries in a freezer environment would be a bad thing as well. Cold temps tend to slow down the process of electron transfer during charging and discharging in normal lead acid batteries so based on that information a gel battery would be even worse imo.
The best description i could find on how batteries react in either environment i found here:
h t t p://72.10.52.249/index.php?option=com_content&task=view&id=29&Itemid=1 (Industrial Battery Products aka: IBP) just copy and paste this url in your browser address bar and remove the spaces i added so it would post on here.

you can do more research or even call any industrial battery provider and you will probably get the same explanation or something similar.
Freezer applications have always been a very harsh environment for electric powered trucks and generally require many special alterations to help keep the trucks running and not freeze up. Heaters on the controls and special batteries, special hydraulic oil, etc.

good luck