Trolling batteries, same make & model, different year

I just got an upgrade to my lousy stock 12v trolling motor. The new 65
lb MK Maxxum is 24v, so I've got to install a new battery, too.

Here's the question. The trolling battery I've been using still seems
to be in great shape, as my onboard charger keeps it in in good
condition. It's a couple years old, but it is a current model.

Instead of going out and buying a pair of new batteries, I'd like to
get a match to the one I have (Interstate SRM-27). It would be a real
waste give up the perfectly good battery I have now.

Is this a good idea?

Thanks,
Jamie
Falls Church, VA