Since the SCAQMD 1113 definitions state "a coating is applied to beautify, protect, or provide a barrier to a surface" it would appear that that's the standard to apply here, although the particular coating type is far from clear. Since 68 g/L is far below most of the coating type limits, seems like your professional judgment as to the closest match should suffice here. There's always the "Other" category...

Note that in another thread on VOC limits, someone reported a LEED reviewer advising them to only use the limits listed in the first four columns of Table 1 on pg 483 of the BDC Reference Guide - those that went into effect on or before 1-1-2004.