If you need to know when a specific inventory item was added to WholeCell, you can find that date on the item's page. Click on the item's ESN or ID to get to its page.
On the upper left side of the page, you will see what PO the device is in, the company that sold it to you, and when it was added in WholeCell.
To view these dates in bulk you'll need to work a bit of Excel magic:
Create an individual Inventory Report that includes the "Age" statistic (the count of days the inventory has been sitting in WholeCell). Download the CSV file and use an Excel formula to count the number of days (Age) backward from the current date to show when each inventory was added.
Here's an example:
To review how to create an Inventory Report, check this article out http://help.wholecell.io/en/articles/2813756-how-inventory-reports-work