I think I've found the answer to this, but only because of a book seller's attention to detail. I don't think it was Portfolio III. I think it was the catalog that's attached.
We know his dad hated his writings. It's possible that his dad got him this gig for Chinese Paintings, but in either case, this would probably explain what happened. His dad probably lied about his middle name and took credit for it.
I also think this also may explain the meaning behind "The Day It Rained At The Los Angeles County Museum." Bukowski always talked about his first story that made him confident about wanting to be a writer. It was about a German WW I pilot.
I think that pilot is the first person he "meets" at the museum, and his father is the second -- pissing on his dreams of being a writer.
Again, see last paragraph...
See last paragraph.
AbeBooks.com: Chinese Paintings lent by American museums, collectors and dealers - November 5 to December 5, 1948, Los Angeles: xx, 45p., plus a lengthy section of appended exhibition photographs reproduced in b&w on glossy alkaline paperstock. Find one plate in color, a fold-out repro situated...