No, it should say "registered Master license". Sounds like it's still using your previous MC 20 Mac license. It's not really a problem for you since your current license will work fine and you can use the master license for future installs on Windows and/or Linux computers. I'm able to reproduce the problem you're having running the MJR install file so we should be able to fix the issue pretty quickly.
For people with an unregistered Media Center who purchased a Master license and are having problems using the MJR file, use the "Restore License" option instead. Just copy and paste your product registration code into the restore license dialog in Media Center. Don't worry about using up a restore out of your annual limit, we'll reset your restore count whenever needed. If you don't have your registration code from the purchase receipt, go to
https://rover.jriver.com/cgi-bin/restore.cgi to receive an email with the codes.