Really depends on how they do it if they do the shrink wrapping technique it'll be just as bad, if they try and use context clues and imagination it'll probably be a bit better, probably never 100% unless they find fossilized flesh (which is extremely rare).

As for how accurate it is with dinosaurs it's gotten better, discovery of certain fossilized feathers has given clues to how they looked, even allowing us to theorize about what colors some of their feathers might have been because the pigments in feathers have different Crystal structures, so in a well preserved fossilized feather they can see the shapes of those structures, obviously the color is long gone but because those shapes are unique to the pigments they can infer what color it was.

There are small details that are never going to be quite right, we have though come a long way from where we were.