I do believe that the FNP45 is truly ambidextrous. The other FNP's you can reverse the mag catch but i think that the 45 has a true ambi mag catch. The safety/decocker on all FNP's are ambidextrous. Thats about all I have. 8)
Here's my experience as a lefty with a new FNP 45.
Decocker, mag release and slide lock are ambidextrous. The slide lock has an internal fork that allows it to operate from both sides of the frame. However, the mechanics of the slide lock operate on the left side of the gun. The fork has enough bend or give in it that pushing the slide lock down from the right side as a lefty might do does not alway work. I sometimes have to pull down on the slide lock from BOTH sides using my thumb and forefinger to reliable release the catch.