If the original owner made an insurance claim, the device in question belongs to the insurance company that paid a claim, and it's not "fair" to help someone make use of something that is not rightfully theirs.
Ok...I'm not going to claim to know
every legal in and out of it, but in broad strokes the Lost and Found Property laws (at least where I live) simply require someone who finds lost property to report it found. If after a certain length of time the original owner has not come forward to claim it, it then becomes the property of the person who found it--it does in fact become "rightfully theirs." (I used to run a movie theater where we had to deal with this fairly regularly.) If an insurance company wants to claim it, it's up to them to do so; the person who found it isn't obligated to track down an insurance company that may or may not have a claim on it.
So at some point it's not only fair, but perfectly legal, as I understand it. It's true though that in this case I don't know how long that waiting period is for the OP--something worth calling the local PD about.