If TV characters were tele-cognizant, they might realize that they usually just appear in Toobworld fully-formed and with no backstory actually lived out. They may talk about their earlier lives, their childhoods, their college years, but the Trueniverse audience doesn't get to see that played out on their TV screens..... Unless they go hunting for it in other TV shows.
All part of the job here at Toobworld Central!
But '30 Rock' was not the first time we ever saw Scott Adsit play the role.
In the 'Friends' episode "The One with Ross and Monica's Cousin", Pete was the director of a movie about Catholic immigrants from Naples and Joey Tribbiani auditioned for a role.