When I bought these, it just looked like they were in protective plastic holders but they are actually "slabbed" which was a surprise as they are small and it doesn't seem worth bothering. Maybe samples to show the type as I can't see why somebody would take the time to do it.
I can't remember where they are listed but I do have another one that is not enclosed in plastic.

I prefer ones that aren't slabbed but thought I'd show these as they seem unusual.
It's not a debate as to whether chips should be slabbed or not, it's just to show them (as I said).
Any comments or information on these particular chips would be welcomed or ideas as to why there are like they are.