"So, my question is...What Fred is showing, are they paste on, plain paper printed inlays applied to used chips?"

Not sure about the used chips part. I would say the rest of your question is right.

I saw those chips. When I was told what they were I never even looked at them close. I was not interested.

"If so, is this done often?"
1st time I ever seen it with a casino chip.
I do believe they were done at the HR.
For that reason I don't doubt they are collectable, just not to me.