If you only trim or edit the clip, making no further modifications (e.g.: don't add any effects, etc.) and then export to the same codec with matching settings of the clip (frame rate, frame size, etc.), then yes. Premiere will smart render the clip. FYI, once you select the matching ProRes codec, you can click Match Source button to match up the settings.
Once you add effects and/or change to a non-matching export setting (frame rate, etc.), then Premiere will need to re-compress.
Thanks so much Trent.
For future reference, you are referring to "smart rendering." ProRes is one of the codecs which supports that.
Hey Kevin, thanks for the info, that'll definitely help me out if I need to look for more info.