Good call- - - -even with the picture enlarged several steps, it's impossible to see if the holes are threaded. Those splined studs might be a little difficult to acquire, so a possible work-around would be a 2-diameter stud- - - -7/16-20 on the banjo housing side, and 3/8-24 through the carrier, then tap the holes in the housing to the larger thread.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!