From a technical point of view, yes. Having "an extra genital" isn't just a question of drawing more pixels. That's easy. The hard part is what you do with it. Is the futa character involved in sex scenes where she's the receiver? If so, you have to consider whether or not the art/animation will make use of that new set of genitals. And even then, in all the futa art/fiction, the placement and positioning of the vagina is rather awkward. And there is no perfectly functional anatomical reference for it to use a base. So it's easy to mess up sex scene alignments in animation due to the awkward ergonomics of the thing, at least, in the presence of balls.
And then there is the narrative part. Depending on the type of game and story you're telling, the presence or lack of female genitals may play a narrative role. Or a mechanical role in the gameplay loop. So, it's not just a question of having it as an option by default, if you can't justify its inclusion in a meaningful way.
But let's keep the discussion of what this type of futa or that should be called out of this thread. Names are used to simply references and expectations, but ultimately, it doesn't change anything. Ultimately, what concerns you is function, and not form.