What's more likely is that you've seen the more common redemption version of these cards.
For a guy living in Hawaii I've had a very interesting time learning about cheese. Specifically, cheese products made by Mootown Snackers, a product line of the Sargento Cheese Company (now a division of Kraft Foods) <vbg> :-}
Okay, a quick explanation. Ever had one of those little cheese snacks that come as foil-wrapped cubes? Same thing except in long cigar-shaped tubes.
Back in 1992, Mootown Snackers inserted one of twenty-four different cards into 5 oz and 10 oz packages of chesse snacks (if you look carefully at the scan below you can actually see an illustration of the packages). Inside these packages you would find one cellophaned wrapped card. Attached to each of those cards was a mail-in offer to purchase the entire set without having to repeatedly purchase package after package of product. And, as you can see in the scan above, for $6.95 Mootown/Sargento would send you a full 24-card set.
What makes this a difficult issue to collect: Cards that were actually inserted into the cheese packages. What's commonly known as the "Mail-In Tab Attached" variation.
Since most of the Mail-In Attached cards were bought by actual card collectors (and not cheese lovers) this led to most of the packaged cards being cut in half and mailed in for the redemption set. Add to that - cards not purchased by card collectors were bought by cheese lovers and parents of little kids, who in turn didn't take care of the cards when they opened the cellophane wrapper. Careless mishandling often led to damaged corners or even bent cards. For those reasons this has become a fairly scarce variation indeed, particularly in mint condition.
You rarely see these cards with the mail-in tab offer still attached. As I mentioned previously, you often end up getting the redemption version. Keep an eye out when the seller mentions "mail-in tab still attached". If he/she doesn't mention it - ask before bidding or purchasing. I've had some good luck talking with card shops in the Minnesota area. Apparently this was one of the mid-states to have actually seen this product on store shelves, so you might want to keep that in mind.

Opened - Inside