They were 100% made for the gift shop. They were even made with the 'VOID' printed on them.
A 'VOID' stamp is not a gaming authorised cancellation for real dice.
While not everyone follows it to the letter they are either supposed to be punched (with a dot or circle) on the 4 spot, or drilled through the 1 spot.

Also, per Rock Olsen's guides, all Caesars Head dice were made with blue print for the logo and head and never white.
.