914 Plug Cap Ohms

They are not precision resistors, the main failure mode is when they increase in resistance, therefore I would say that the values that you have measured are fine.

 Hi Dave

The answer is in the Maintenance Manual Heavy, Look for section 74 on electrical.

Spark plug connector 4.4 to 6.0 kΩ

As Kevin noted the real issue is high resistance that exceeds 6.0K as this will have an effect on starting or even misfire.  remember that all electrical values are given at room temperature values.  (20 to 25C)  If checking a hot engine the value will go higher.  

Cheers