When should we scope integration with SAP backend?

In the early C4C days, I seem to remember that one had to scope in integration with ECC/CRM at the very beginning of a new C4C project. Activating this integration at a later stage (after data had been created in the system) was not possible.

Over the last 2 years I think I read somewhere this behavior is not true anymore. You can activate the integration at a later stage.

Can anybody confirm it is now possible?

Cheers