The above website shows pictures of how Golden Pothos leaves look as they mature in the wild. Apparently, they can look a lot different than most of us are probably used to who don't live somewhere tropical. Anyway, take a look!
I wonder if giving them the pots is enough to get the leaves to change. Age alone doesn't seem to do it. Perhaps they need a different kind of light or humidity.
Location: SW Idaho, USA
USDA hardiness zone: 6
Elevation: 2,260 feet Profile post