I have been in this situation with two (Ambient) stations at one house during a transition. What I found found is that may be you can have your console or software display the sensor (type) ID, but if you cannot, or even if you can but both are of the same type, you still won't know which one is "hooked up".
Generally, when you first power up a console or ObserverIP it goes on the lookout for RF transmissions from the/a sensor. I do not know whether it waits until it possible sees multiple transmissions from possibly different sensors and then selects on the basis of signal strength, but it does not appear that way to me. My situation involved different models (different IDs) of outside and inside sensors, but both outdoor types were supported by both devices. It appeared my console/OIP would select the first one from which a transmission was received, and then "stay" with that one.
I needed to power cycle and play with timing of that to "catch" the sensor I wanted. If both happen to be almost synchronized in timing, this would be next to impossible to do and you may need to remove batteries from one, or press the outdoor reset, to de-synchronize them and allow locking in to the desired one this way. Suffice it to say this would not work if one of the multiple is a neighbor's!
I don't know what would happen if there are two sensors with the same ID (model). I can easily see that there is nothing unique about either sensor that way and you would alternately receive data from either unit. Whether that would show up in software, where reporting might be in largish intervals, remains to be seen. If both are received in a single reporting/updating interval, you might just see the last one. Either way, this scenario could be problematic with no workaround I can think of.
If you are in control of all sensors involved, one possible solution is to have multiple console/OIP share the same outdoor sensor and simply take the other one down.