Update: I did upload my receipt from apple store to the Skylum website. Moments later I also sent a message to them through their website. I got an email this morning asking for the app store receipt. I email a pdf of it to them and they sent me an activation key number and a download link for Luminar 3. The key is the same as for both Luminar 2018/Luminar 3. So now I have a both software installed and running. Looking forward to playing with Luminar 3 over the holidays. Got a couple of weeks off.
Thanks for the thoughts all! Will look forward to reading more about your experiences soon.