Typically, the receivers are wideband, supporting both 1310nm and 1550nm signals; although they may be optimized for one versus the other.  The optical signal will experience different attenuation (loss) characteristics at the two frequencies and the cards may have different optical transmit levels, so the optical receivers will see a different receive level on each end of the link.  As long as the optical receive levels are within the operating range of the receiving line card, the system will typically operate error free.

Using matched cards on the link ends typically helps when troubleshooting as well as sparing equipment.