Listen to those who know. This is returned goods, no duty, no fraud, I've done this exact thing when I've had upgrades done with my Canadian build equipment (US to Canada shipment).
If you list value as $50, how would that bring up red flag, this is entirely different shipment than when album was shipped to you. Does customs have xray vision and photographic memory to recall this was originally a $1200 album!
And why would you have any morality problem with the $50 valuation, in essence there is no actual goods changing hands, so duty being charged twice for goods that didn't change hands, that's extortion.
As for being fearful of customs, where is the jail for customs cheats, $1200 is relatively nothing in the whole realm of goods going through customs. If caught the worst you'd suffer is hold on package, they determine value, you pay the duty they determined, package continues on it's way.