Sounds silly, doesn't it? It's just a staple, after all. What does it matter if you remove it to make a copy?
Believe it or not, a number of probate cases have been turned on their heads because somebody took out the staples on an original will, presumably just to make a copy. Why? Because probate courts have ruled that an original will that has multiple staple holes in it is evidence that 1) the will has been tampered with (pages removed and replaced), or 2) the testator (person who signed the will) intended to revoke the will by taking it apart.
Staple holes aren't the only seemingly innocuous things that could invalidate a will, either: writing on an original will, especially if you've lined through a part and/or written something different in the margin, may well invalidate that will - again, because it is seen as a revocation of the original will and an attempt to make a new one without "the formalities of law". That's one of the reasons we always give the client a copy of every estate planning document we prepare - for making changes that don't invalidate the original.
There's nothing more frustrating for a probate attorney than having to tell the client that her husband's will won't be accepted for probate because he wrote on it. The differences in who gets your stuff between testate (with a will) and intestate (without one) in Texas can be significant. You paid good money for those estate planning documents, make sure you care for them properly.