UD,
As you correctly state the grey top scheme is present on many Russian aircraft.
Even the land based Russian Navy Su-30SMs are in the scheme.
39 - Russia - Navy Sukhoi Su-30SM at Ramenskoye - Zhukovsky | Photo ID 621891 | Airplane-Pictures.net
Some of the Russian Air Force Su-30SMs are also in the scheme.
01 - Russia - Air Force Sukhoi Su-30SM at Ramenskoye - Zhukovsky | Photo ID 617481 | Airplane-Pictures.net
VFC-12 US Navy Agressor Squadron recently painted some of their F/A-18 Hornets in the scheme to represent the Su-30/Su-34.
https://www.facebook.com/andrea.arlo...09915119302252
The die-hard conspiracy people went nuts claiming that there were being painted up in Russian schemes for "false flag" ventures in Syria.
https://www.metabunk.org/debunked-us...raining.t8018/