The Insight can no longer be unlocked for Autopilot (Nav II).  This is due to the breakup with Trimble.

You may be able to find a used Insight that has the Autopilot unlocked.  I'm unsure what you mean by plug & play to replace the old display.  The Insight was the first Ag Leader product to use a CAN setup so there would be no predessor to it.

It would be possible to replace an Insight that was not unlocked with one that is but this would require rebuilding the configurations on the newer display.