|Car 990 began service 1 Aug 1933; pg 186|
The diner reminded me of the streetcars in Charles Smallwood's The White Front Cars of San Francisco that was published by Interurbans in 1978*. Harry's was a real place, so I leafed through the book to see if by some wild chance Harry's Wagon might be in there amongst photos of repurposed cars. No dice.
Naturally, the book is jammed full of streetcars that look quite similar to Harry's Wagon, but there's no obvious match, and no reference to that diner. One major difference: Harry's has a 4 window front, and all the similar streetcars had only 3. Maybe Harry's was reno-ed? Can't say for sure.
*I bought this book back in January after seeing an ad for it in an old issue of Railroad Model Craftsman. On a lark I looked for it online, and found one for $5 plus $10 shipping. I bit and the rest is reading history :-)