Common for older Rvs to have convertor/charger, power distribution units ,to have all 120v breakers and 12v fuses under small metal door. Also common color was brown if in interior and side toward near the pedestal cord. These older chargers were not multi step, keep batteries watered. There are add on multi step chargers or fairly priced modern replacements. Old ones are fine while camping and using the battery, a decent maintainer while parked will help instead of keeping plugged in to prevent overcharging.
Midas is popular vintage find someone will be along with good info .
95 Monaco Crown Royale
M11 400hp, 4060 trans.
Aquahot, Generac Guardian7.5k