Always use the same date for updating the physical count, as you used when you froze the inventory. Yes, the Inventory Trial Balance Report for the 12/31/2017 date should provide valid balancing to the General Ledger. As a side note, to be sure you are not having any balancing issues... the Current Inventory Trial Balance should balance to the current Inventory Valuation Report (or use a future TB date of 12/31/2018). If you see significant differences between the TB And the Valuation Report... well, then you have other challenges.