Equalization can't HURT them. Whether it will help, will depend on the condition of the batteries and what (if any) damage or wear is on them. If the two were installed in parallel and used in parallel...properly...there's no reason they would have different voltages unless there was some damage. If the wiring
wasn't quite equal and one had cycled deeper or more often than the other...it could just be worn down more, forever.
Follow Lifeline's instructions (which are specific to their product) and see if it helps. I'm not sure I'd want a battery shop messing with my batteries, too many of the guys at them really aren't rocket scientists. Since Lifeline recommends routine equalizing, you might want to invest in the right equipment
to maintain those expensive batteries in any case.