I think you mean the D7000! (D7k is an easier differentiation).
Although they may be from the same maker and have similarities, The D7k sensor has a slightly different spec to the K-5 sensor. I believe Thom Hogan says that the Nikon sensor is their own design, whatever that means! Here are some of the differences (from DPReview, compare side by side).
D7k v. K-7
Effective MP - 16.2 v. 16.3
Sensor size - 23.1 x 15.4 mm (3.55 cm²) v. 23.7 x 15.7 mm (3.72 cm²)
Pixel Density - 4.6 MP/cm² v. 4.4 MP/cm²
But both seem to have some early QC issues, that's why I've never been keen on being an early adopter, but hey, someone has to do the beta testing!
As a long time Pentax user until early this year, I have a soft spot for their gear, but not their QC in recent times. I personally prefer the D300s sensor to either the K-5 or D7k (I have tried both), it just seems to have better colour and overall rendering with the RC's that I regularily use (NX, Silkypix Pro and LR3).