[Empiricist]

Generally speaking the Russians used the original C-47s, not their licence-built Li-2s, for VIP flights. I do not know TBO for C-47 and Li-2 for their various elements and systems but I had an opportunity to compare quality of various airframe and engine parts of both C-47 and Li-2. I was shocked by very poor Li-2 quality and corrosion throughout, meanwhile C-47 with its anti-corrosion coats is very well up to this day. That is why I can understand why Soviet decision makers chose the American product to fly, not their own.

Below: Russian General Nicholas Petrov in Edmonton. He also flew by C-47. Soviet dignitaries were able to forget about nationalistic propaganda "Russian-made is the best".