No, they are not the same species.

As far as I know, the West Indian whistling duck officialy just "Indian whistling duck" or mostly known Lesser duck (Dendrocygna javanicais) inhabit in South-Southeast Asia (It is not reside in America)

There are two species of whistling duck living in America, the Black-bellied Whistling Duck, (Dendrocygna autumnalis) and the Fulvous Whistling duck (Dendrocygna bicolor).

But actualy the Fulvous Whistling duck are looking quiet similar as the Indian whistling duck.

The Fulvous Whistling duck got dark grey bill and brown bellie, the Black-bellied Whistling Duck got red bill, and black bellie. This is the best way to distinguish from each other.

I shoot on Fuji Velvia and Astia, with Nikon F6 and Pentax Z1p with Sigma zoom lenses.