If you have a country coach conversion the clue for whether or not they built it with chassis battery trickle charger is there will be a circuit on the AC breaker panel that will be marked chassis charger and that breaker Powers up an outlet in the engine bay that they'll have it plugged in to.
If they didn't put a chassis battery charger they still had an outlet in the engine bay and the block heater will be plugged into it andthat breaker on the AC panel will probably be marked block heater that powers up the outlet in the engine bay.