Someone WAS paying attention!
Exactly right! A single battery charger will charge a parallel string just as if it were one battery. Since the capacity is doubled it will take twice as long to get to the 80% charge level (when the battery reaches the float voltage for the battery) but charging the remaining 20% will take an additional 12 to 18 hours, the same for each individual battery alone on the charger.
You should set the charger as you would for a single battery.
There are two types of fools...
One says this is old, and therefore good..
The other says this is new, and therefore better...