Tested this on my 2160 and got the same result. I can't remember trying to dub a finalized disc to the hdd before, but you can dub an unfinalized disc to the hdd. So, if the disc you want was recorded on the Magnavox, you can undo the finalization, and the dubbing option will now show.
Dazed and confused over high tech.
Sigh...Concrap. The Internet Overlord Cometh
They're not com-tastic!
The help file on Dubbing Finalized and Unfinalized discs to HDD is here.
A list of other help files is here.