Two of my first three models were (and still are!) Chalkies, so the topic has been one of both extreme interest and deep research. I’ve been collecting them and tracking them for years: it’s a far more complicated topic than most collectors realize. It’s further complicated by the fact that a lot of collectors don’t even know what a Chalky looks like. What many collectors advertise as chalkies are nothing of the sort. A lot of them are simply early, matte-finish models with clear topcoats.
The precise date of introduction of the matte finish is debatable: I tend to think the first true matte-finished models were actually the woodgrains, which were introduced sometime around 1959. As for the more horselike colors, I’m not so sure when that occurred - the documentation for that time period is, as I’ve mentioned before, rather thin and hard to date. By 1962 at the latest, I’d think.
What the woodgrains and the early matte finishes have in common is a clear topcoat: after the model was given its basic paint job, it was painted over with a clear, satiny finish, presumably to improve the durability of the paint job. The raw, unpainted plastic was simply not left exposed on a matte finish model. (On gloss finishes, it was hit or miss. Again, a little more complicated than you might imagine.)
This "clearcoat" has some distinguishing characteristics. One, it tends to puddle and drip, just like some glossy finishes do: you can see the dark or yellowish drip marks usually on the underside of the belly and other drip points such and the lower lip, tail tip and (ahem) boy parts. Here's a nice belly spot from a Family Arabian Mare:
A lot of these topcoated models also have "waffle marks" on the bottom of their hooves. Waffle marks look - well, like waffle indentations, and are presumably from the racks that the models were either painted or dried on. Those that don’t have waffle marks often have a rough or dirty footing, sometimes with bits of wood embedded, presumably from another type of rack or shelving.
(Yes, I know this particular model is actually glossy, but this is by far the best example of waffling I have, and the same racks were used anyway.)
Because there is no exposed, translucent white plastic on any part of these models, and they have a rough footing - the two most commonly quoted characteristics of a chalky model - those unfamiliar with a true chalky often confuse these matte-finished models for one.
The clearcoats were gradually phased out starting in the late 1960s; partly out of cost and possibly through improved painting techniques. It’s still used occasionally on alabaster or light gray paint jobs, for both added durability and a little extra added finish.
The clearcoat also came with a couple of liabilities. One, it tended to turn yellow. A lot of collectors don’t know this, but there are two different ways a model can yellow: either the plastic can turn yellow, or the finish can. And the finish that turns yellow is the clearcoat, not the colored undercoat. (Yellowed clearcoats respond better to bleaching techniques than yellowed plastic, though.)
Clear topcoats can also turn slightly opaque, or "milky": it’s usually seen in the nooks and crannies of a model where the clear topcoat could puddle. It’s most commonly seen on woodgrains, but no matte-finished model is immune (it’s less visible on alabasters and grays, of course.)
Aside from the yellowing and milkiness issues, the matte clearcoat finishes have generally held up better over time than the later unclearcoated ones. I've found that they're definitely easier to clean: most everyday dings and scuff marks don't get past the clearcoat. A little gentle cleaning, and a brief trip to a sunny window, and voila! As good as new.
