HH,
I have few questions.
What version is running currently and what version are going to?
How many application policies do you have?
Do any of your policies have XML profile?
Do you have any ASM specific iRules?
Taking an archive will back up all your ASM policies along with the rest of your configuration. If you are really nervous about this though you can also (depending on how many policies you have) export each of the policies and save them off too.
I have been managing ASMs since they were TrafficShield and have gone through a few major rev upgrades. It is not all that different than LTM, in fact during my last upgrade I think I had 2 ASM policy issues and the rest were LTM related bugs that I ran into. I am happy to help where I can.