Can you tell a Russian from Ukrainian? Can you even tell an Ukrainian name from Russian name?
This is akin to asking if someone can tell an German name from a French name. Sure, there are some shared ones, but for most intents and purposes locals can easily tell the two apart.
Wow. Can you tell a Korean person from Chinese person? Polish name from a Czech one?
Different cultures, different languages, it's obvious to the locals.
There's a bunch of phonetical differences:
Different suffixes: Ukrainian surnames often have no suffixes at all (more often than in Russia): Although it doesn't say anything about a person's nationality for certain because of migrations.