Quote:
The pack card on top has the date in which he can start sell a particular stamp.
Nowadays, the pack card on the top has the statement "do not sell before the first day of issue as announced in the Postal Bulletin" presumably because first day of issue dates in recent years have been VERY fluid. Take for example, the Lydia Mendoza stamp that was slated for March and has now been moved to June 2013. The stamps are already printed, I'm sure, so it's more cost effective for the printers to omit the specific date of issue when preparing the stamps for distribution.