If it is a company owned device and on BES, I would not try to do the upgrade. Could cause more problems than its worth. Might even lead to termination, if your company is so inclined - I know some are. They will know you did something as they would have to reactivate the BB on BES after you do an upgrade.
Even after you upgrade, you might not be able to do the things you want to do due to a restrictive IT Policy. Also, keep in mind, there is NO personal info on a BES enabled BB.