Jon,
Using a multimeter you can measure the impedance from the female hot pin to the male hot pin. It should be either 1K or 10K. Alternately you can read the values off the resistors (if you know the color code). The first resistor on both units is 1Meg but the next is either a 4.99K or a 49.9K (the lower value means you have a 1K attenuator). You can measure the resistors with a meter as well. However, just a visual inspection will not determine anthing unless you can read the color codes. Hope this helps.
Ric