Don't see any problem with the suggested dating of the spoons, and you might find the old thread linked below interesting, despite the missing images - your spoons are typical of those discussed, and unless the pics are very deceptive, yours appear to be silverplate worn to brass, which isn't uncommon. So far as I know, there is still no definitive information on their origin, and up until now, personally, had only seen these from Japanese cities, most often Nagasaki - so yours being from Hong Kong is unusual and brings just a bit more information into the mix...
viewtopic.php?f=13&t=35086
~Cheryl