I don't think so. The veins aren't right in the leaves, plus don't most rudbeckia have hairy or fuzzy leaves?

Some species of Rudbeckia do, some don't (have hairy leaves). But that said, I'm not sure of the identity of this little seedling.

not rudbeckia.

I used to grow a great variety of rudbeckia. Every year it would reseed. But then it petered out and haven't had any in a couple of years until this year. One lone plant came up. I'm nursing it along and will have flowers soon. :-)