GUID issue

Hi,

we will be upgrading from EBP 2.0 to SRM 5.0. i have the following questions.

1 - will the Business partner GUID be changed, after we do the system upgrade ? what will happen when we migrate the employees from HR system again after the upgrade ?

2 - there is no concept of Central person in EBP 2.0. ? how the central persons will be created in SRM 5.0 ? where do we define the number range for Central persons in SRM ?

Thanks in advance