Hi Mark,
Probably, but not necessarily- it depends on motor power. The source is VBATT, which is the '+' silkscreened 0.1" header on the processor board and each motor driver board, but keep in mind those are through the 32 pin connector- it's only rated for 300mA. You can push that rating enormously in a one-off project, but if your motors are much of anything, it's probably best solder a power connection to both motor driver boards(probably a long 0.1" right angle header).
Don't forget to remove/cut one of the address resistors

let me know how this works for you.
Thanks,
Ben