WW's the expert on this, but...
IIRC, the idea was make it as fast as possible, and since the development began before the V-1 was employed, it wasn't because of the Buzz Bombs. I think from the factory, they came with a slick wing, 6X.50 cals and no dorsal. As soon as the 56th FG got their hands on them, they began adding the dorsal fins, added the extra 2 guns, and hung the pylons under the wings for missions.
The pylons were removable, as they were on all P-47's capable of carrying pylons. I guess for operational purposes, they were always either flying with bombs or fuel tanks, and so you always see them hung.
Again, maybe WW will chime in a correct me if I'm wrong on any of this.