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Presumably the assayer is АЯ. He would be Aleksandr Ilit Jaschinkov alt. Jaschinov in St. Petersburg 1795-1826. He was a rascal and got the sack. The maker is unknown to me. Let's wait if someone has identified him.
Let the auction houses write whatever pleases them. Check yourself from other sources.
Unfortunately I don't know which one version is correct. Both surnames appears in various sources. No big deal as long as we know who is in question.