Kaon are a well known brand in Aus and a relatively large scale operation (when compared to many of the other Grenadier accessory suppliers). I don’t think you should have any doubts about their legitimacy in terms of taking your payment and dispatching your goods.
Having said that I found the packaging on the shelf and molle panels to be fairly basic and the bare minimum required (they traveled 1100 miles to reach me). They are only pieces of steel and therefore inherently robust but not sure they would stand up well if subjected to abuse during transit half way around the globe. Maybe ask them if they take any additional packaging measures when freighting overseas.