Really from the description of the part. Each color scheme has a 3 letter code. For 2013, AJM (Glass Sparkle Black and Metallic Oort Gray), AJN (Pearl Glacier White and Metallic Oort Grey) and KGK (Marble Daytona Yellow and Glass Sparkle Black). The cowling piece for each color is listed, in this case COWLING, SIDE RH (GRAY) FOR AJM (
94450-15H50-YHG). The last three of that part # is YHG which translated to the part I provided, TAPE, SIDE COWLING RH FOR YHG (
68685-15H40-AJ7). Not the easiest, but it works for all the side cowls I have looked at or purchased.