How to measure Clock frequency of PIC?
Try a 10x (not 1x) probe on the OSC2 pin. You should be able to see the clock. The frequency will be slightly changed by the probe loading. 

I don't think your part number is correct, but most 16F chips are similar. 

Edit: Scope probe loading is explained in this Tektronix paper.

Crystal pullability is explained in this application note. Note that the typical loading from a 10x scope probe would only change the frequency by perhaps 100ppm (0.01%), which is unimportant in many applications other than timekeeping.