@mb: Nope. Once those copies are gone, it immediately loads up the next game for sale.
I think you may have misunderstood what MB was asking. It is a "marketing stunt" if you think they're being deceptive and pretending like there's no room left for all the ones and zeros in their warehouse, so they need to get rid of those 150 copies of SiN Gold and then they're all sold out. But that's not really the case.
The limited availability just refers to the amount of a specific title that they can afford to sell at these crazy discounts. All these games will still be sold on GOG, just back up at their regular prices. It's the discounts that are available for a limited time.
That's what I was saying, just in a simpler fashion.