回复：回复：you are fine

What 'sleepyblue' meant was that normally it takes time for the actual GC card to be made and sent to you, so when someone's GC is approved, the officer will stamp on the passport to show that this person now has valid GC status, in case he/she needs to work or travel. When the actual GC card arrives, the card will become the permanent proof, replacing the temporary stamp on the passport.

Maybe you didn't need interview so card is sent to you directly without getting the temporary stamp. Anyways, you have the GC now so you are fine.