When I got my replacement K5 from Pentax due to the stain issue, the box serial number has a circle next to the SN. We've concluded that it means the camera is deemed stain free.
What camera and from where are you talking about? There is also Gray Market which for all intents and purposes is the same camera but may not come with all accessories and will not have the same warranty as a camera bought in your local market. Refurbished cameras will usually be Sold as such and it could be anything from a repair/overhaul to simply a returned camera that cannot be sold as New but has been freshened up by the factory service (cleaned, repackaged, etc).