I was looking at the same drive you bought while I was at Staples today. Ultimately, though, I wanted a BenQ, so I opted for the external Pacific Digital for a bit more money. I learned earlier from their tech support guys that, if you look down near the PacDig UPC symbol, you would see a Rev # and that #4 was the BenQ 1620 OEM. So, I bought that instead and it came with a firmware that started with a 'G' but flashed easily to a BenQ 1620 for me.

Best of luck.