Never mind. Noxon works. With quite a bit of rubbing, the fingerprints that were embedded on the bottom of the tray disappeared. Unfortunately, so did the numbers.
I always thought that, when a motherboard manufacturer refurbishes a burned-out or bricked board, not only do they replace the faulty chips, circuitry, capacitors and resistors, but they also replace the dirty, rusted or broken (non-electronic) parts, to make the item look respectable, if not "like new".
I traded a new motherboard that came out of the box bricked, for an RMA motherboard that arrived looking used, judging by the crusty CPU tray under the board. I hope it doesn't give me 4 beeps (or any unacceptable alarm sound), like the one I sent to ASRock.