Both Jim and Liz Beloff ONLY ever play the Fluke and Flea on stage.
Jim Beloff and his sister and her husband, Phyllis and Dale Webb started the Magic Fluke company, which makes all of these instruments, so you'd expect that he'd play them...
If you find videos of him after the founding of the company, showing him performing, you'll see this.
There's one video of him with Lyle Ritz, dont remember which song, but he's playing a Fluke...
I have video from the Morristown Ukulele Festival back in Aug 21 2013, that I shot with my iPhone of him performing a few songs, but it's not online as of now, but when he went up o the stage, there were 2-3 Flukes and 2-3 Fleas on the stage and some were played and some might have been as backups.
In the IT world, they call this 'eating your own dog food'.
If there's enough interest, I'll try to get the video online for others to see - let me know.