Cops like Gottlieb live in the moment. The manufactured notes are an expediency. His primary concern is the criminal trial. He's got an investment in Nifong now, so his concern is to bolster Nifong's faltering case. In for a penny; in for a pound. There may be a thought about a civil trial in the back of his mind, but he doesn't have a dog in that fight other than some thought of general revenge against these rich northern boys (in his mind) just for being rich northern boys. Gottlieb's bread gets buttered on the criminal side of the case, not the civil side.
I tend to agree it is Gottlieb's response to what he perceives are the immediate demands of the situation. He is unlikely to have asked himself, what happens if this report is demonstrated to be fabriicated. He is likely to have what fighter pilots call "target fixation" - a nasty way to hit an obstacle or get hit.
We can over-analyze this. Normally the simplist line of reasoning is the most accurate. We have seen nothing to suggest that Gottlieb has more than your avergae smarts (indeed somewhat the opposite).
What I also wonder about is the level of oversight the DA's office had on this. It is so bad, surely Nifong did not see it - preserving plausible deniability.
What would be great is if we can come up with another piece of Gottlieb fiction and compare the two to estimate just how much help he had writing this travesty.