Yes you will need something unique in your fields.
Although the 2D symbol looks unique to us Archicad just sees it as a 2D symbol.
I am assuming you have one object that can show different lights.
Using the object name is no good as it is obviously the same for all 3 lights.
But in the object you must be setting a parameter to choose a particular light.
So use that parameter in you fields.
Or as Eduardo suggested use the ID and make sure each light (or each type of light) has a unique ID.
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