Are you talking about the Bluray case covers or the outer box?
The case covers
Oh. I went low tech on that.
In Windows 10 I just did right click, print on the cover image from file explorer (NOT the photos app). Unclick fit picture to frame, set page size 8.5x11. Click options -> printer properties, so now you have access to the full printer properties. Make sure to set borderless off. That seemed to print out the right size for me.