There would still be a discrepancy in that they would be moving much faster than they would have if they started from scratch. The difference is usually very easy to tell, you'd have to be extremely good at covering your tracks if you wanted to start from another code base and you copy bit-by-bit. Copying gives a completely different pattern than writing does.
There are ways of using information other than copy-pasting it in. A reference here and there when you get stuck, reading ahead to avoid dead-ends. They would also be moving much faster if they were just very good, and Google was already paying this guy on the understanding that he was the best. Picking that apart could be difficult-to-impossible.
Or maybe Uber's just complicit. But you're introducing facts not in evidence based on your assumptions about how this went down.
