For the most part this is true, but I have seen photos of really different patterns on some of the nijsseni-group species. Usually it is strange dark markings on females.Those species that only come in one form (such as panduro and nijjensi) are likely to be close to wc form.
I remember when we could only get ugly yellowish-gray specimens in the 70s. Then wildcaught specimens appeared in the trade. Now they are rarely collected commercially. This is more likely due to them not inhabiting the more common collecting areas and domestic commercial breeding makes collecting in the wild uneconomical.My vague understanding is that while they are among the most prolific of species most are in regions of Brazil that are not exporting them for various reasons however - there are true experts who know the actual details of what is happening.