We'll be blunt and admit that the language barrier precluded us from reaching a conclusion, especially since the supposed evidence we received was vague to say the least. As it turns out, however, the allegation became a hot topic in South Korea, at least enough for Samsung to take to its official corporate blog in order to dispel the rumors and deny such a practice exists within the company. According to the piece, (translation by BusinessKorea), nothing of this kind is happening at all at its manufacturing plants:
Indeed, according to Samsung, recycled AMOLED displays are only offered to consenting customers, who are in need of a repair, in order to lower the bill. Moreover, Samsung says that the aforementioned whistle-blower is not employed by the company and that it isn't clear if the plant seen in the video (below), where an employee is allegedly outfitting a Note 4 unit with a recycled AMOLED display, is actually a Samsung factory.
So who's right? Quite frankly, until we can see some tangible evidence, we're inclined to believe Samsung, but we'll keep our ear to the ground in case this goes any further than it has so far.