Toyota didn't recommend a 5W-20 for this application.
OTOH, many 5W-30s of the time would have sheared to twenty grades anyway.
If this car typically crawls through Miami Beach traffic with the AC blasting or if it's driven to NYC every other weekend four up with gobs of gear in the trunk at speeds never less than than ninety or so, a 5W-20 might not be suitable.
If the car is driven normally and doesn't see a lot of heavy traffic or hard highway runs, then a 5W-20 would probably work.
You won't know until you try it and UOA it.
You won't do any serious harm in using it.
Maybe a couple of notches more wear metals in a UOA but nothing catastrophic.