Cap'n Kobold
Hero
As I understand it, not really. The Dark Powers are fairly central to the concept of Ravenloft, and are most definitely in charge of it, but are very different to deities in the FR.If you're considering a total conversion of the module to FR, then you can probably find a counterpart in the FR pantheon that matches the Dark Powers, don't you think?
They have no need to be worshipped as FR gods do, don't even reveal they exist in most cases, and don't grant spells.
They have a level of power over the Demiplane of Dread that pretty much no FR god has been shown to be able to exert on the material plane. They also interfere with some of its inhabitants in ways that I think FR gods are unable to or forbidden from doing.
In the Forgotten Realms, gods are just powerful NPCs. The Dark Powers of Ravenloft are almost direct stand-ins of the DM.