"Expressly authorized by the company" means they want you to ask permission to conceal carry if you are legal to do so, is how I interpret, no guess on their willingness to grant permission.
No weapons in a work-owned vehicle actively being used for work.
That is a very poorly-written handbook policy. The final sentence referencing "employee's vehicle" is a non-sequitur to "company vehicles" in the first sentence. I'd be willing to bet that some genius took the alcohol/drug policy and swapped in "guns" where it previously stated "drugs."