I saw a near mint nickel that my my friend has and I don't think he would ever carry it. There are more lightweight and affordable modern options that would serve your purpose. You wouldn't have to worry about it getting beat around. Unless you just want one. JMO, James.
They wear very quickly. The anodized frame scratches very easily. The pre-12's to the -3's all had narrower frames than the other K's and there are subtle differences in the thicknesses of the hammers and grip frames. This is only significant if you want to replace a bobbed hammer or reinstall factory magnas should they be absent. Correct parts are tough to find.
12's are decent guns and under appreciated I think. Most users won't buy one for serious use because the factory says that they are not to be used with +P ammo. Collectors pass them by unless they are NIB and cheap.
Watch for cracked frames in heavily used examples.
I've got a few of them here that I ended up with in trades and I have to say that the Round Butt, Tapered Barrelled 4" is a joy to use..... even with standard loads...