The reason it's a blemish or factory second could be many. We have very stringent quality control so sometimes there are some extra machine lines or an edge isn't the way it should be, a lot of people may not even be able to see it, but if it doesn't pass our QC team then it gets put aside for this sale.
On all regular priced items, we offer a 30 day satisfaction guarantee, a customer can buy it, try it, use it and if for any reason they are not fully happy with it, they can return it for a full refund. If it's been used or even mounted, it's not new anymore so that would be marked up from mounting and blemished. On this same note, all Black Friday sales are discounted and as such, are Final Sale.