Most of the time, I prefer originals to ensure the schematics are readable, and aren't a photocopy of a photocopy or have pages that are taped together.
However, sometimes there are errors in the originals that are corrected later.
Quoted from Friengineer:I was thinking about laminating them
Don't laminate it. That will ruin any value. That's like taking a perfectly good pinball machine, chopping it up, and turning it into a coffee table.