Prewar KGs are a scarce commodity to start with, and their configuration shows almost perfect proportion for their size (or at least the round butt version does; the ones with square butt or extension stocks can look pretty unbalanced and ungainly). I think the tapered barrel has a lot to do with it. The Model of 1953 KGs are quite similar but just don't have the same visual appeal to my eyes. Once I saw my first prewar KG, all the subsequent small-frame adjustable sight .22s just looked slightly out of proportion, even unfinished.
Consider the math: prewar KGs were in the company's production line-up for only four years before WW2 interrupted commercial production. In that time, the serial number range that included the Kit Gun increased by only 6000 -- from (round numbers) 529500 to 535500. That count includes not only all the Kit Guns manufactured, but all of the tail end production of the .22/32 Target Revolver (originally known as the Bekeart and at other times the .22/32 Heavy Frame Target or the .22/32 Hand Ejector), and continuing production of the .32 Hand Ejectors, including the square butt Regulation Police variant. I don't know the production breakdown for these separate models, but I don't see how the Kit Guns could have accounted for more than 1500-2000 units of the total at the outside. I actually think the production may not have exceeded 1200, and I have heard S&W collectors who have been in this game far longer than I have suggest that there may have been no more than 1000 of them. Compare that count to the count for other desirable models: Triple Locks (about 20,000 total), Registered Magnums (5000+), the Prewar .38/44 revolvers (11,000 Heavy Duty, about 5000 Outdoorsman). You can see why the Kit Guns might be hard to find and expensive when they turn up.
There is one artificial component holding up the asking prices (but not the selling prices) of these revolvers; the Blue Book, for reasons that I have never completely understood, thinks that Prewar KGs in the best condition may be worth $7000 or more; you will see that figure cited from time to time in Gunbroker ads for guns that never move even though they are priced at one half or even one third that level. I wonder what the market knows that the Blue Book doesn't? There are recorded KG sales above $4000, but I believe these were flukes in an overheated market about three or four years ago. I believe the same guns later traded hands at lower prices.
I bought my first prewar KG about 18 months ago. At that time the prices had already started to slide. The first gun I bought had gone unsold for months at $3000 and had been marked down about 20%. I took it at that price, though in retrospect I probably could have shaved another $300-400 off the price. The next one was similarly priced high condition gun, but with a box. A few months ago I acquired a 90-95% gun for less than $1500.
I love these little guns; I have deferred buying other uncommon models in order to keep funds available in case one of these shows up at a reasonable price. These days I think reasonable means $1500-1800 for a 90-95% gun, and $2000-2400 for a better one with a box. Almost all listed KGs that I know about come with prices or minimum bids that exceed those values. And I think that is why they are still listed, though months have passed since they were first made available.
A thread like this needs a picture, so here's a KG from 1938.