that is incorrect, all genes have a heterozygous (aka het) and homozygous (sometimes called super) form. Pastel, Yellow Belly, Lesser, het albino, het clown are all heterozygous (het), while super pastel, Ivory, BEL, albino, clown are all homozygous.
being het has nothing with being recessive, co-dom or dom. we just drop the "het" when we talk about co-dom and dom because its visual, doesn't mean it still isn't het.
To the OP: Just call it a yellow belly, its how we talk in the reptile world, we shorten words and drop assumed words... just what we do. Makes it confusing for everyone else lol. the het ivory is just assumed so we don't say it. we don't call pastels, "pastel het super pastel."