Soviet Awards to non-Soviet personnel.

[CtahhR]

I just purchased a 14 award documented group to a Bulgarian Colonel which included a Twenty Years of Victory medal which I find a little strange as not only was it issued in 1972 but the Colonel was not awarded any other Soviet or Bulgarian medals for participation in the war (except the Bulgarian 40 years of victory). Can anyone give some explanation of why the Soviet authorities found him deserving of this decoration? He was born in 1922 and joined the BCP in 1946 but it doesn't seem that he was a participant of the Patriotic War although he was issued an international passport by the Bulgarian authorities. Attached is a scan of the important part of his document.