When should I rewrite my dll when using coyote to write unit test?

Question

I am trying to write some unite tests based on coyote. I found that in the tutorial I should rewrite my assembly before coyote test command.

However, when integrate coyote tests into unit test platform using TestingEngine, it explored bugs without doing any rewriting manually.

Did I doing the right thing? If I can explore the bug without rewriting assembly, what the operate exactly works for?

Thank you!