Polarized connectors would be helpful because they won't allow you to accidentally plug the negative lead into the positive connector and vice versa (assuming they're soldered on correctly). For as 2 pin Deans connector, I think most are "polarized" in the fact that the connection is made with one socket and one pin, which means there's only one possible configuration they can be connected in.
Just to be careful, make sure the pins on what you order look like this:
and not this:
Either way, since LEDs act like diodes, the worst that will happen is that the LED module will need to be disconnected and reconnected if connected in reverse. Even if powered on current will not flow backwards through an LED unless it exceeds the LED's reverse voltage threshold; since the XQ-E is designed to withstand 5V of reverse voltage the LED should be able to handle SF batteries even at full charge.