It is not better. It is newer. You may get a cleaner camera that has been used less.
I have had both "versions" and I haven't noticed a measurable difference.
Actually, the more time your K3 racks up, the quieter it runs and the easier it is to wind.
Of course you want to keep it clean.
I have a minty older K3 that runs quieter than my newer version.
This kinda is like what happens to engines as they break in... At 60,000 miles of normal operation your cars engine will put out more horsepower than it did right out of the factory. Right out of the factory it will be tight. After some normal wear and internal friction will reduce and it will start to feel it oats.
As your K3 gets older it is always a good idea to time a run of 10 feet through the camera and see if the camera speed selector is correct at 24fps or if you need to dab some paint on your speed setting if it has changed.
10 feet of film should run by in 16.7 seconds at 24 frames per second.
Using a normal stop watch, you can time this pretty well. No need for a strobe light or anything fancy.
SC