The installers should / should have done an optical test. If it wasn't done, you should do it / have it done.
Basically a calibrated light source is used at one end, and an optical power meter is on the other. This provides a number representing the attenuation of the span.
The attenuation is subtracted from the overall output signal of the transmitters.
If the signal level is within the acceptable limits of the receivers, then no attenuation is required.
If attenuation is necessary, you are usually doing well to use variable optical attenuators (VOAs) because the characeristics of the transmitters (and receivers) will change over time and you may find it necessary to reduce the attenuation after a while.
The connectors are not significant (aside from the obvious physical differences), you'd want to order a zip cord jumper with the appropriate ends to match your panel / WIC and the switch/router interface.
Post again if you have any more questions.
Good Luck
Scott