Walter - probably yes.
That I am aware there are 2 colour blindness tests. One is used by the USA Authorities and their half the world, the other is used by the UK Authorities and the other half of the world. Naturally, HKG is in the UK camp and holding a USA Class 1 does not mean the HKG CAD will issue you with a licence.
If you want to test the water, do a UK CAA Class I Medical Exam.
- I should add. You could do a HKG Class I medical too. If the HKG CAD are prepared to issue you with a licence, then Dragonair couldn't give a rats ar$e about your eye sight. All KA want is a Class 1 Medical Certificate issued by the CAD.