Not sure if there was a stock batt charger. Our 89, 28' had nothing but perhaps it was an option.
The 86, 32' we got used had what could have been a stock charger or at least installed by the dealer when the boat was new. It was a Guest, 2 bank. I think it was 15A. It really did not meet the charging and house load needs, imo.
-Karl
1986, 32' Sedan, twin 360ci, 275hp Chrysler's w/ K&N flame arrestors