How do I tell if a Symphony I/O module is MK II or MK I?

For Symphony Mk II modules, not all Mk II modules are marked with a "MK II" sticker on the front of the module to indicate this is a MK II module. 

However this does not necessarily mean that the module is an older original Mk I module. 

You can determine if a Symphony I/O module is MK II or MK I based on the shape of the PCBA board. 

For original MK I modules all PCBA boards will have a partial cutout as shown below:

For current MK II modules, all PCBA boards will be fully rectangular in shape as shown below: