If you have a copy of great-great-grandfather's deed, is it:
- the original which passed down through the family
- a copy of the official record at the courthouse (which is a transcription of the original)
- a copy of a copy a relative made
- a copy from a microfilmed copy of the original
Perhaps the copy in the courthouse had some notation in the margin in an ink which did not show up on the microfilm. Perhaps the courthouse transcription contains an error. The courthouse transcription does not contain the actual signature of the individuals, which the original should. And on it goes.
We could pontificate on citation for a long time, but I won't (at least not here). Suffice it to say that not all copies of a record are created equally. And that a complete citation should get you back to the material you copied or transcribed. Then you know what you used and if a more complete copy becomes available you might want to obtain it.