Can a normal USB C panel mount socket be used to receive USB PD?
If you are making something for your own home office or garage, you can use whatever low-voltage connectors/wires you want, including Type-C connectors.

However, these connectors are designed for high-speed communication with low-profile portable devices in first place, and power delivery is sort-of secondary. As high-speed (10 GHz range) connectors, they typically have 0.5mm pitch and target thin 0.8mm PCBs (half of normal PCB). These parameters are hardly "convenient" to deal with.

More, the Type-c and PD requirements are that initially the connector/port should not have any voltage, and ony if a special signaling over CC wires is detected, the starting voltage is "+5VSAFE", and only after heavy negotiations over PD protocol it is allowed to supply higher voltages. 

And I don't want to start about the cost of Type-C cables.

So, for projects like 12-V lamps, it is more convenient to use old-style DIN connectors, like this one, which are better manageable in DIY environment: