Very obscure #vinyl #record query

I work at a number of stations in Alaska. At one station I found this 'unusual' Vince Guaraldi album - Oh Good Grief!
The station manager shared its unusual feature.
Side one is 'normal' but Side two is Grateful Dead, Anthem of the Sun.
(They discovered it one day on the air)
I have searched around, but no one/forum seems to know anything about it.
As a former recording/mastering engineer, a couple of things come to mind.
Good Grief is listed as WS1747
Anthem of the Sun is WS1749
Could be master platters got shuffled?
Also, there are copies of Good Grief listed from 1968 with some coding/ numbering errors, but those have the smaller WB logo, this one is bigger, and presumably later? Also, most Anthem of the Sun dics (that I can find), have an even different WB logo, but I did find a couple listed on line, with the same WB logo as this Good Grief!, and described as being a repress. (not a good picture, from eBay, but shows the same WB logo)
I'm very curious if anyone has run across this - surely they didn't press just one like this.
Thx
Some pics: