You would have to view it,trace out what components go to what driver,determine the values of the resistors,capacitors and inductors and once that is done probally feed that data into a spice or simulation software program to determine what type of crossover it is,slopes,phase and its cutoff frequencies would then be able to be determined;at least this is my guess.
Maybe Bill Legall from Millersound might be able to help you out if he is close to your location or at least give him a call for his ideas;Bill is considered one of the top speaker/crossover people in the industry.
Millersound
1422 Taylor Road
Lansdale, PA 19446-1531
(215) 412-7700