The order in which disclaimers and signatures are applied is determined by the order of the Policy Patrol rules and whether you select to 'prepend' or 'append' the disclaimer/signature.
If you have two prepend disclaimer rules that apply to the same mail, the disclaimers will be applied as follows in the message:
Prepend Disclaimer 2
Prepend Disclaimer 1
If you have two append disclaimer rules, they will be applied as follows:
Append disclaimer 1
Append Disclaimer 2
To change the order of the Disclaimer Rules, go to Rules > Rule ordering.