High Country:
It would all depend on how well it was packaged prior to freezing. With the head still on I recommend to customers to leave the head on the outside of the hide preventing slippage from taking too long to freeze. This will however cause the ears to freezer burn faster than if the head was on the inside of the hide. I recommend that if your bear is to be in the freezer linger than 8-12 months than you will want to finish caping and insulate the packaged bear protecting it from freezer burn. Contact the taxi you want to do your work and consider having them flesh and salt the bear that way freezing is not an issue.
Either way, I have successfully thawed and tanned bears that have been in the freezer for 2-3 years.
Good Luck
Kuduman