Manufacturers took advantage of loopholes and leeway in the regulations, but as far as I am aware (and I have been following dieselgate closely), no cases have been found where manufacturers produced falsified documents.
They falsely stated emissions that they could not in fact do in practice. The cars were registered and license plates issued under false pretences.
If the correct values had been provided, the cars would not have been street legal. Getting them registered anyway is fraud.