To me it always seems that the seller is either unsure what it is they have got exactly, or that they also believe that people might not know it's "rare", because their prospective customers are slightly dim and don't know exactly what they are looking at either, so have to be told it's RARE, just in case. Plus it justifies the rather silly price.
It's also probably likely to be because the extent of their research on the item extends only to eBay. Everyone else has put RARE in their title, ergo, it must be RARE.
With that in mind, most people who actually know what they are looking at, would only buy the item if the price is right, or it does indeed include some choice bits which have accidentally made it into the listing, to which the seller is likely to be completely oblivious too.

Basically, the seller is likely to be a little clueless about what it is they have got, and will probably wrap it in crisp packets and cereal boxes if you decide to bid on it, and actually win.