How to populate serial numbers in IB records when the part was set up for no SN control?

A part number was erroneously set up in the item master as having no serial number control.  They will be changing the part setup within a day or 2, but 36 of these items have been sold and shipped.  My user wants me to update the installed base records with the appropriate serial numbers they should have.

Presently, a SN field does not display on the IB "General" tab as it normally does.  Should I expect this (blank) field to appear on the form, once the item is set up for SN control at sales order issue, or will it remain missing, since at the time the IB was generated, there was no SN control?  I'm wondering whether my user will be able to update this data for herself (preferable) or whether a data fix is in my future.