Review for LEGO set 6362 Post Office from Brickipedia
“Although there were sets released with printed bricks with the text Post, this and set 6651 Mail Truck were the first LEGO System sets that involved the postal service. The post office contains a counter, a storage for letters and a section for parcels. It also has two mail... More boxes. The set includes six letters (printed 1x2 tiles).”
Full review at brickipedia.fandom.com