AIR CHINA BOEING 737-800 Silver Peony Landing to Sendai Airport

Air China Boeing 737-800 B-5178 Silver Peony Library landing to sendai Airport in Japan.
The Peony painting series of Air China has painted peony in Airliner.
There is a gray peony in a color similar to this airplane, but the aircraft registration is B-5176.I think that how to distinguish between these two aircrafts body paints is the color of the aircraft registration and the turbofan engines.

AIR CHINA BOEING 737-800 Silver Peony Landing to Sendai Airport

Airport&Runway:Sendai Airport Japan.(SDJ/RJSS) R/W09
Airline:Air China(CA/CCA)
Aircraft:Boeing 737-800(Boeing 737-86N)
registration:B-5168　Silver Peony Paint