What make and model numbers for the batteries?
Option #2 doesn’t sound like a marine/deep cycle battery. 87ah lead won’t go far or last long.
Cranking amps (cca) doesn’t mean all that much to a GEM. It’s the reserve capacity that’s important (Ah).
You can get group 31 marine (deep cycle) lead acid batteries from o’reilly for about $100 each, but you have to water them periodically. 105Ah.
If you go with #1 it sounds like it may be gel batteries based on the price, make sure your charger is set up for gel. Not all stock chargers from the 2000-2004 era can work with gels.