When a new boat leaves the factory is there a tolerance or acceptability for the evenness of the bottom running surface?
What about a seasoned boat been on the water, sitting on a trailer

some boats have a build in rocker ....and some run better with no rocker..all depends what you mean by evenness ?!

so called blueprinting, is not actually to make the bottom straight..its more to suit the boat in its best running ability.

Which boat, and do you have pictures of the bottom ?

Yes, most production (and custom) boats do have tolerances for flatness of the bottom - among other things. The most critical area is the actual running surface and some builders (on certain models) actually build rocker (think smile) or hook (think frown) into that area for a variety of reasons. For most boats though, perfectly flat and level is the way to fly.

As for boats that have been around for a while, many things can reshape the running surface, Improper storage on a trailer, lift or blocks is the most common way to mess up a bottom. Oddly enough, most boats seem to gain hook instead of rocker. Hook drives the bow down and scrubs speed off. Rocker does pretty much the opposite.

a good trailer is a must..roller trailers are terrible as loads sit a small area...long bunks that extend past the transom preferably 4 are the best...