Hey... Those contacts are on the outside of the device, so they must be buffered. You need not worry about damaging the device while working with them unless you try something stupid like plugging them into the wall.
One of the contacts is connected to a rather large area of board trace. Generally, that means that contact is ground. So, based on that assumption that leaves only a few options
1. Analog-to-Digital converter. On the SGS series of devices, USB pin 4 - 5 form a mode switching device which allows you to put the device into download mode with 301kohms of resistance, or UART with 619kohms of resistance. there's a total of 20 modes including car dock, home dock, audio test modes, and different physical buttons like play, pause, fast forward.... This is highly likely
2. 1-Wire communications. This is basically a serial input/output on the same line using an additional ground as a reference.
3. This is a qualcomm device. It may be that that is an ENABLE line for QPST download mode. Try this, remove the battery, short the 2 questionable contacts, plug the device into the computer and insert the battery. If it enumerates with a different USBID... that's what it is.
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