At NasaSpaceFlight.com, Chris Gerbhart writes:
The RD-180 has provided exceptional performance to the Atlas V and was chosen to be the engine of the first stage in no small part because of its safety record and reliable performance track record.
Who flew the RD-180 before it was used on Atlas III? They flew 6 Atlas III flights, and then transitioned to the Atlas V.
Ya, the bigger brother RD-170 was flown on Energia on the side boosters and became the standalone Zenit booster. But who else flew the RD-180, to give it a track record before the Atlas V?
If as Wikipedia suggests that the Atlas III was the first use of the RD-170, then what was the Russian intent in developing it from the RD-170 core?