A multimeter with diode tester might be able to give you a reading of the zener voltage
(use a needle to get to the broken off leg?). You get a lower (probably around .6 - .7 volt) reading in the forward direction, but should get around the zener voltage in teh reverse direction.

All multimeters with diode test might not go as high as 6.2V - you might rig someting up with a battery/power supply and a series resistor and the diode. With a power supply > 6.2V and the diode in the reverse direction you should be able to get a voltage reading across the diode close to the zener voltage. Use a resistor high enough that the current is kept low enough not to cook the diode...

/Michael