well, ideally you should have an oscilloscope for this kind of thing but theres a couple of logical tests you can do. For a start, if the resistance is zero between the sockets then they are probably connected together and are patching multiples, although you could see that from the inside. I think from the look of it that this is the most likely option.
If there is voltage at the sockets you can probably tell what it actually is by seeing what control or parameter alters the voltage i.e. if the voltage rises and falls along with the envelope then you've probably got an ADSR output, likewise with an LFO etc.
If the voltage is consistently very low or non existant on your meter they may be audio sockets, though god knows why. This is where an oscilloscope comes in handy for seeing what signal is actually present but you could always just plug it into something and see what comes out.
Are there main CV and gate inputs and outputs round the back? If not the sockets could be something to do with that.
Good luck
