Some of the Maltese sellers assemble klickies from whatever factory-reject parts they have.
Quite right.
I wondered if some of these parts were from the white plastic used to clean through the injection moulding machines between different colour runs. That might explain the different feel of the plastic and the fact that all the parts look so similar.
Ah yes, I forgot the injection mould cleaning stuff, that could be it as well.
Like Tahra I too insist they are not custom (resin-made, original colour scraped or pealed off, or whatever) but factory-made, on purpose or by mistake.
I myself have a very small amount of very similar parts, like f.e. 2 pair of legs. The material is indeed a little different, therefore I haven´t used them (yet) on my (customised) white COLOR-klickies.