Where does the expression "to shine someone on" come from? And does it have racist origins?

It's a hard phrase to search for. A Google N-Gram search for "shine him on" offers a number of hits in accord with the definitions in the questions.

In the following, the phrase is described as an "old theatrical expression." In this case an actor says the script writer recognizes the script's weaknesses, and thus the actor doesn't have to "shine him on:"

https://www.google.com/books/edition/All_His_Jazz/5Vr0l7Ux2OAC?hl=en&gbpv=1&dq=%22shine+him+on%22&pg=PT191&printsec=frontcover

All His Jazz: The Life And Death Of Bob Fosse By Martin Gottfried (1990)

According to GDoS “shine” in shine someone on and other related expressions is a euphemism for shit (a US black usage).

Shine someone on (v.) (also put someone on (the) shine, shine it on, shine on someone) [euph. shit n. (1)] (US black) to ignore, to disdain. 1968

• 1968 [US] ‘Sl. of Watts’ in Current Sl. III:2 41: Shine it on, v. Forget about it; don’t pay it any attention.
• 1969 [US] Cressey & Ward Delinquency, Crime, and Social Process 808: If an initiate arrives on the scene and presents an image of being ‘rowdy,’ ‘lame,’ or ‘uncool,’ he is immediately ‘put on the shine’ (shunned).

in our (white) working class neighborhood we used this to imply that someone was being duped, or ignored, or deceived in some way.

"He said he would, do it, but you know he's just shining us"

"if you can't come and get me, just stop shining then, I'll find another ride"

"I asked her to come, but I guess she said "shine on that!" after I was gone.

Just my opinion, but any racist origin could be the stereotypical newsstand shoe shiner, convincing a less wary victim to "sit down, sit down it will only take a second boss"and with enough spit, and polish, and hustle, an old boot might briefly pass as new. The shine won't last and you've wasted a nickle.