POs are still Federal property and that's generally a no-go for carry. IIRC it's mandated by state check out Hadgunlaw.us for more info...but I still wouldn't carry to the PO.
In the past there was always signs on all the doors at my local Post Office. I know there has been some debate on P.O. carry. The past couple times in the P.O. there has been no signs on the door. Did something change?
No debate. It IS Federal property and as such......No-Go. Just plan your errands accordingly as I and most others do, it ain't no biggie. Having a Federal charge IS a biggie on the other hand.