The stamps you see on the image above are actually for the most part US Revenue Stamps. While at one time the US Government would tax each deck of cards they stopped collecting taxes on them in 1965. At that point many of the manufacturers started just putting their logo on the stamps. We list the name of your organization and a number count to keep track of how many decks of your souvneir cards we printed.
Getting your own "creative collectable" is a big step for most organizations. Having it as a "LIMITED EDTION" deck not only adds to the collectability side of your playing cards, but it increases the value and lets future generations know how many decks of your cards were printed.
When we first started doing souvenir decks in Circleville, Ohio we were asked why we didn't "limit" the amount of decks or why we didn't mark how many decks were printed so that collectors would know how many were in circulation. After doing them without limited edition, numbered seals for so many years we have decided to include it as part of our standard package now.