I have been a volunteer on many archaeological "digs" and have cataloged many thousands of relics. I can tell you unequivocally that his method of identification bears little resemblance to professional archaeological notation.
When doing an archaeological survey the area is first gridded off into "units" that are typically 1 or 2 meters square and then are sub divided into quads. That way each artifact can be placed accurately within each unit of the grid by triangulation. Traditionally, you start in the southwest corner and label each unit with a number. The first number refers to the east-west location and the second number refers to the north-south location. For example, unit (1,1) is the southwest corner and unit (1,2) is one row east and two rows north of that. (the corner starts at 0)
Each artifact is then cataloged according to the position that it was discovered in it's respective unit both by location and depth, it is then numbered and placed into a bag according to each 10 CM of depth, (below the root mat) A description of the object as well as the time and date is usually documented as well.
GG~