Flacoman,
that page shows the piston for the 2V 4.6L engine. If that piston doesn't work out, the pistons for the 4V 4.6L engine are identical except that the "dish" is recessed only .060" instead of the .152" like the 2V.
Or you can probably get just about any shape you want from an aftermarket company but the OE ones may be cheaper. Or they may be alot more, I'm not really sure.
As for the 3L pistons, they are domed .027".
(According to the Federal Mogul Piston Catalog).
Bob