it varies.
most `pre-airs` tend to be leaks of finalised versions shown to industry
reviewers/critics to generate press buzz/coverage prior to airing, and don't
change.
rarer are "in-house" early pilots, made to hawk around networks or advertising
sponsors to get an airing deal, or to get feedback from focus groups before
the final decision on cut or content or casting is made and pitched. these
generally appear much longer in advance and are the ones that tend to differ
significantly.
not that the reviewer screeners are cast in stone - i dare say if a show gets
universally panned then the studio may do a recut, or even recast/reshoot a
part if the reaction is excessively negative. obviously it's much more
difficult and expensive to do it at such a late stage, so it's not so common.
