Intentional or not?
When Chalky met with Jimmy, the first thing he said was "How those shoes fitting?". Jimmy's reply, was something about them being tighter than expected. But that metaphor is usually the other way around, where the shoes (the job) are larger than expected, and harder to fill. A sign of respect and humility.
Jimmy is saying he's bigger than the job; or
Jimmy's not worldly enough to understand the metaphor; or
the writers blew it.