I was recently in a used car dealer where a 2001 Corvette sat in the showroom. I got in, opened the glove compartment and found the leather portfolio containing the owners manual. I made use of the leather cover which has a couple business card pockets on the inside and slipped a couple Corvette Action Center promo. cards in there.
So yes....the 2001 Corvette owners manuals come in a leather portfolio case. The reason why you probably don't have one in your car if you bought it used is because these are often sold over EBAY to make some money by the original owner.