Setup Costing 3 months after Inventory, will system capture all the transactions in Costing and GL?

If we enable the Costing setups 3 months after Inventory, will system capture all the transactions in Costing and GL?

Let us say we dont setup Costing and start with Inventory Transactions, after 3 Months Business decides to setup Costing—Will the system pick up the 3 Months Transactions in Costing and GL when we start with Costing Setups, will system pick up all?