In one of my quadcopter flight class, we were taught that the motors are identified as M1 to M4 starting from the front-right (front starboard) then counting counter-clockwise. If I Google the same, I get varying results.
So is there a universal and correct shorthand to identify the motor placements on the Phantom (or any quad for that matter)?

"Universal and correct?"  Not a chance with all those wacky mavericks out there building there own Frankenstein creations!  

But sure, most flight controllers have standard configurations that I suppose you could consider as "guidelines" and "suggestions" to help you keep from crashing on your first flight.  I'm sure you noticed there was more than one quad configuration so it depends.  Usually you have to take the direction of flight into account as well -- as shown from one of the DJI diagrams below.

Excellent! Thanks gil.

So for all generations of the Phantom, they're all configured as "Quad-Rotor X", which confirms what I know.

If you're interested there, there may be some more information you can use on the DJI wiki (which is where I got that diagram)

http://wiki.dji.com/en/index.php/Main_Page