So, we can carry in federal buildings now?

[redneckbmxer24]

I dig all these bullshit restrictions getting uplifted. It defies logic and reason how firearms could be banned in post offices, yet you can legally bring in one to ship that you're still clearly in possession of. A little piece of absolute fucking stupidity removed.

Mizelle said that while post offices have existed since the nation's founding, federal law did not bar guns in government buildings until 1964 and post offices until 1972. No historical practice dating back to the 1700s justified the ban, she said.
Mizelle said allowing the federal government to restrict visitors from bringing guns into government facilities as a condition of admittance would allow it to "abridge the right to bear arms by regulating it into practical non-existence."

 

[sawgunner2001]

I'm pretty sure OP is referencing:

UNITED STATES v. AYALA (2024)​

United States District Court, M.D. Florida,​

UNITED STATES of America, v. Emmanuel AYALA, Defendant​

Decided: January 12, 2024​

The short version:
Ayala worked as a truck driver for the USPS. He routinely carried a handgun in a fanny pack. When USPS OIG attempted to arrest him, he fled. He was later arrested by local PD and charged with federal counts of knowingly possessing a handgun in/on a federal building and for resisting arrest.

Ayala argued that the ban on carrying on USPS property/in USPS buildings was a 2A violation per Bruen's 'history and tradition' test. He also argued that since the attempted arrest was for an unconstitutional law, that the resisting arrest charge should be thrown out also. The US District Court judge agreed with the first argument, but not the second.

It should be noted that the court making this decision is a trial court that does not set precedent for the whole United States. It is likely this will be appealed by the .gov to an appeals court. Precedent will (may) be set later. If you carry on .fed property, including USPS property based on this court case, you're still in violation of the law (for now).

Sources:

https://caselaw.findlaw.com/court/us-dis-crt-m-d-flo-tam-div/115709647.html

and

 

[Gommer]

No, it’s not a precedence setting case.