Johnny Cakes - S6-E8
Continuity mistake: When Tony and Julianna are sitting down to sign the contract, he picks up a pen that is lying on top of the contract. Immediately there's a cut to the contract with the pen still lying on top of it. (00:48:00)
Answer: That's not Jimmy, just a look-a-like. Jimmy's short and stout, the guy in "Christopher" episode is tall and medium built. The hair is also different.