More than likely, the inductors are not close to the same values so it will be easy to tell the difference. The larger the value, the larger the inductor. And inductors do not have a polarity. It doesn't matter which direction they are mounted.
Based on the
instructions, it should be pretty easy.
L14 = 0.25mH 20AWG Air Core Inductor - Tweeter circuit. This will be the smallest of the inductors with the smalled guage wire.
L15 = 0.47mH 18AWG Air Core Inductor - Mid circuit. This is the next smallest inductor. Wire guage is the same as L16.
L16 = 2.2mH 18AWG Air Core Inductor - Mid circuit. This is the next to largest inductor. Check L15 to make sure they have the same guage wire.
L4 = 4.0mH 15AWG Air Core Inductor - Woofer ciruit. Biggest inductor of the bunch.
-Robert