You forgot to mention that OSSE has observed to other weapons in Ukraine that have never been in the possession of the Ukrainan Armed Forces, and therefore must come from Russia:

R-330ZH Zhitel: 
August 2015: http://www.osce.org/ukraine-smm/177826
June 2016: http://www.osce.org/ukraine-smm/247216

TOS-1 Buratino, 220mm:
September 2015: http://www.osce.org/ukraine-smm/186276