Once the plugin is enabled, the Content | Links edit form will offer Date and Time fields like those of the Content | Write form. The original Date/Time will be NOW for new links. Change that as you please, and when you save, an additional update query is run to apply the timestamp to the link.
Note that entering an invalid date may show a not-so-elegant error message.
Note the plugin only works with TXP 4.2.0 and up as it depends on the new