My guess is based on the large % difference between the average retail price of the OS version vs. the price of this offer and on the fact that the title does not say "OS"...
Just so every knows, Buydig often does bait and switch on Ebay. For past Western Digital 1TB portal hard drives deals, they sent different models with minor differences in specifications but nevertheless still different. I wouldn't be surprised if they send an OS version. OS version on Amazon is around $144.00. Selling a $199 lens for $112 seems implausible.