Russia cries “sabotage” after Slovakia questions quality of Sputnik vaccine

"Russia denies" bad behaviour is such a common refrain that there's a subreddit dedicated to it.

https://www.reddit.com/r/RussiaDenies/

I'd be more surprised if the sputnik vaccine actually did work as reported.

What are the methods available today to determine if received vaccine are legit?

From the text of the article I've got the impression that instructions itself received with different batches (and by different parties) differ. But how country officials can check that vaccine they received is the one that they bought, short of starting using it and tracking the result.