Storywise, this is yet another disposable Chan story, industrialized movie-making.
There are two things of interest here.
One is how the needs of the Chan franchise ferret out peculiar corners of the American national story. In this case the US was well into the beginning of administering regions in the Pacific. This gave opportunities for new kinds of crime and the novelty of the crime was one of the attractions of the series at this point. So we have the smuggling of colonial currency, an esoteric illegality and the use of new weapon, a "knifethrowing" pistol.
Ho hum. I suppose that will be interesting to historians. But for students of film there's a lesson here too. What do you do if your story depends on matters of race and you want to exploit that but also want to bury it? You fold it into other narrative elements of race.
For those who don't know the franchise, it was very long and successful. It stars a white guy pretending to be a Chinese master detective, the acting mostly through a halting English and a few phrases like: "a hasty man can drink tea with a fork." Incidentally, this fits in an odd place in the detective genre because we never really see any detecting, any real wisdom. The only thing we see is him setting traps with the trap revealing the hidden crook. He never figures it out directly.
Back to race. Chan's race is hidden twice. First, we have one of his sons as "assistant," a comic, bumbling idiot. This truly is racist and deliberately so. The contrast between the son (played by a real Asian) and his lack of insight and his father is amplified by the physical appearance and the obvious appearance.
And this is further folded or shadowed (an appropriate term) by the black guy. He is placed as far from the son in all dimensions as the son is from the father. He is that much more comic, and independently clueless, and also independently "ethnic." Its a vile notion to exploit by today's standards, but the method of shadowed folding is clear.
Its a device used in literature, but much more common in film because you can link so many more qualities in parallel, here all aligned to "detection" qualities. That Africanamerican's name is Chattanooga, derived probably from Jack Benny's "man" Rochester.
Ted's Evaluation -- 1 of 3: You can find something better to do with this part of your life.