While otherwise minding his own beeswax, Bill Mullins spotted a “quite dashing” cameo to bring to our attention:
I don’t know if you follow stuff like this, but in a 2013 Rocketeer comic book, Nick and Nora Charles make an uncredited guest appearance.
The original creator of the Rocketeer, Dave Stevens, had died, so the art isn’t near as good as the original comics.
The redhead and the guy with the monocle and bowler derby in panels 3 and 4 are Ham and Monk from the Doc Savage books — also uncredited.
If this is something anyone wants to chase down, the comic is The Rocketeer — Hollywood Horror. It also has some H. P. Lovecraft overtones.