Yes, some sellers would seem to think a thing is rare if (a) they have it for sale, and (b) they don't stumble over it every time they walk down the street.

In my eBay auctions, I have started to use and print this classification system (based on Seymour's in Antique Gambling Chips) in all of my poker chip auctions:
extremely rare, rare, scarce, uncommon, average, common and very common

Robert