I keep a copy of what you call "wrong", but what the IRS calls "Original Return" for due diligence.

I've had to defend a number of clients, successfully, but for the case of amendments, I had to disclose the digital copy of both the Original return and the Amended return. Separately.

Hence why there are explicit instructions to make a copy and rename it, which I usually append "As Filed" onto then go about doing the 1040-X on the Original Return.