Diary of a Bookseller/ Music Desk?

I've been reading The Diary of a Bookseller (2017), recommended by librarian Steve at Shadows & Light and written by the owner of a secondhand bookstore in Scotland, Shaun Bythell.

The diary is not jazzed up, it's very much the daily goings-on at a bookstore, which I recognize, except for the book-buying bits, since all the books I handle at the thrift  store are donated.
Even then, I pick and choose what to put out, and to some extent what to price it.

Far from the juiciest parts of the book for a casual reader––that would be his descriptions of customers, I imagine – it's what Bythell says about book selling that interests me most. A lot of it validates or sheds light on what I'm dealing with in my little corner of the business.  

That Amazon is a monster monopolist, for instance, I knew, but even to the point of having bought ABEbooks (which had been started by booksellers and still looks that way)? 
That I did not know.
Damn.
It's like there's no little corner of The Shire left.

Then, I'd wondered the other day as I priced the twenty-bags of shiny, like-new hardcover crime thrillers at my usual 49-cents each if I was really right in pricing them so low.
But that's Bythell's valuation of that sort of bestseller too.

"What passes for a best-seller in the new book market is precisely the sort of book that will be a dog in the second-hand trade.
Perhaps people who buy into the best-seller concept will always buy their books new, to be on the crest of the wave as it breaks rather than the troughs behind it."

 That makes sense--there's a lag time between when a book peaks, and when we get deluged with copies of it. Can't give away Dan Brown's DaVinci Code now, or the Girl with the Dragon Tattoo, or Girl on the Train, etc.
They are yesterday's news.

Bythell continues:
"Perhaps also because the Dan Browns and Tom Clancys of this world are published in such vast quantities that there is never any scarcity value in them for the dealer or a collector."

Yep.  

His tales about customers inspire me to start jotting down more of my own exchanges.
Yesterday a couple came in looking for adventure books.
Wild, by Cheryl Strayed?
Already read.
Treasure Island, by Robert Louis Stevenson?
Too old. (?)
A serious biography on Columbus as an Adventurer? 
They turned up their noses.  

The Fellowship of the Ring, with a personal recommendation: "I'm just rereading this"?
Yes! 
. . .But the only copy we had was too beat up. They would go buy it new.

MYSTERY:
I bought at my store this fantastic piece of furniture for a laptop desk.Thirty-five measly dollars. I LOVE IT!

Any idea what it was made for originally? It's got musical instruments on the front...
Michael (and Elaine)?