Differents between TP-51D Standard and TP-51D with 2 seats conversion kit

[PMOX]

Hello everyone,I'm new in this forum, I write from Italy and I don't know much about the details of the various variants of USAAF fighters and my question is this: which is the difference between a TP-51D (TF-51D) standard and a TP-51D (TF-51D) with 2 seats conversion kit? Where can I find photos of the cockpit architecture of these variants?
Thanks for your attention!
Mox