Engine New Engine - Retune Necessary?

Unless you are changing out the Ford racing intake, there should be no reason to change your tune. Tunes are needed to basically calibrate the MAF to the new diameter of the CAI from stock, or perhaps changing the location of certain sensors that change their readings. The computer will calculate the air fuel mixture determined by what is picked up by the O2 sensors. Having said that, you are correct that every engine can be tweaked here and there to get max power out of it, and only a true dyno tune can accomplish that, but I think the gains would be minimal.

From what you're posting a re-tune is not required

If you have not changed anything in a major way like the displacement of the engine, camshafts, intake or adding headers etc. the tune you were using should work fine in my opinion. Others can chime in a correct me if I'm wrong on this, but I think you would be good to go tune wise with just a basic long block swap.