The Russian Athletics Federation said on Monday that Shustov's ban was dated from June 5, and his results were disqualified for a period from 2013 to 2017.
However, while the machine as a whole remains immobilised, individual parts of it have begun revving back into life.
36-year-old Guerrero is now free to lead his country in their first appearance at the tournament.
Indian boxers were cleared of any doping violation, but they remained under the scanner for breaching the Games' strict 'no needle' policy.
The IOC said that 584 samples from London have been retested and 49 have come up positive with 21 of those coming from Russian athletes.
Russian biathlete Yana Romanova, who has been disqualified, said that she would rather "throw it in the bin than give it back to the IOC".
Russia's entire weightlifting team was banned from last year's Olympics for repeated doping cases.
Javelin thrower Rohit Yadav has been provisionally suspended after he failed a dope test conducted by the NADA.