That was my interest.
So far I could not find out what cameras soviet sports photo reporters had in that period at such important events.
Zenits are beyond my imagination.
We have thread at rangefinder.ru - "what cameras professionals used". One of the guys who worked this way told us how at very first chance all FSU was ditched and it was Nikon. But only few were able to get Nikon in USSR for official assignments. Rest of photojournalists, professionals used Kievs and Zenits.
I know that at the GDR news agency reporters going to western events from some time on used Nikons as these got motordrives something what on the home market only the long outdated Praktina and the shortlived Pentacon Super offered.
However I got proof that at least one soviet photographer used a Nikon within the USSR. And so far I found on the net more photos of soviet photographers using a Linhof than their western collegues...