If you really don't want to unmount the driver to look at the polarity, you can use the down-and-dirty installer trick which is a 9v battery.
Apply the battery to the speaker leads, noting which wire is touching the + side of the battery. If the speaker moves out, that is the correct positive wire (mark that wire so you will know it is positive). If the driver moves in, that is the - wire (and would be an out of phase condition if you wired that lead to the + side of the amp.) You are applying a small amount of DC current so only touch the battery long enough to see the cone move. Do a google search for more info on the topic. YMMV, no warranties implied, yada yada yada
