As far as I could ever find out, this is what's known about Royal Hawaiian ukes:
- they were made for the Royal Hawaiian hotel to be sold to tourists
- they came in a range of qualities - some were pretty rubbish, others quite good
- they were made by multiple different builders across decades
- there are no records from the hotel to help further
So you're left looking at the uke and making guesses. This one is almost certainly not by Kumalae in my opinion. It looks quite like the ukes Kamaka made and still makes, but that doesn't mean it was made by Kamaka. Date: not new, that's all I can say!